diff --git a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
index 14aa6f2..ef3d6ed 100644
--- a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
+++ b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
@@ -18,19 +18,43 @@
 
 // Package dns implements a dns resolver to be installed as the default resolver
 // in grpc.
-//
-// Deprecated: this package is imported by grpc and should not need to be
-// imported directly by users.
 package dns
 
 import (
+	"time"
+
 	"google.golang.org/grpc/internal/resolver/dns"
 	"google.golang.org/grpc/resolver"
 )
 
+// SetResolvingTimeout sets the maximum duration for DNS resolution requests.
+//
+// This function affects the global timeout used by all channels using the DNS
+// name resolver scheme.
+//
+// It must be called only at application startup, before any gRPC calls are
+// made. Modifying this value after initialization is not thread-safe.
+//
+// The default value is 30 seconds. Setting the timeout too low may result in
+// premature timeouts during resolution, while setting it too high may lead to
+// unnecessary delays in service discovery. Choose a value appropriate for your
+// specific needs and network environment.
+func SetResolvingTimeout(timeout time.Duration) {
+	dns.ResolvingTimeout = timeout
+}
+
 // NewBuilder creates a dnsBuilder which is used to factory DNS resolvers.
 //
 // Deprecated: import grpc and use resolver.Get("dns") instead.
 func NewBuilder() resolver.Builder {
 	return dns.NewBuilder()
 }
+
+// SetMinResolutionInterval sets the default minimum interval at which DNS
+// re-resolutions are allowed. This helps to prevent excessive re-resolution.
+//
+// It must be called only at application startup, before any gRPC calls are
+// made. Modifying this value after initialization is not thread-safe.
+func SetMinResolutionInterval(d time.Duration) {
+	dns.MinResolutionInterval = d
+}
diff --git a/vendor/google.golang.org/grpc/resolver/manual/manual.go b/vendor/google.golang.org/grpc/resolver/manual/manual.go
new file mode 100644
index 0000000..82fcc2e
--- /dev/null
+++ b/vendor/google.golang.org/grpc/resolver/manual/manual.go
@@ -0,0 +1,130 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package manual defines a resolver that can be used to manually send resolved
+// addresses to ClientConn.
+package manual
+
+import (
+	"sync"
+
+	"google.golang.org/grpc/resolver"
+)
+
+// NewBuilderWithScheme creates a new manual resolver builder with the given
+// scheme. Every instance of the manual resolver may only ever be used with a
+// single grpc.ClientConn. Otherwise, bad things will happen.
+func NewBuilderWithScheme(scheme string) *Resolver {
+	return &Resolver{
+		BuildCallback:       func(resolver.Target, resolver.ClientConn, resolver.BuildOptions) {},
+		UpdateStateCallback: func(error) {},
+		ResolveNowCallback:  func(resolver.ResolveNowOptions) {},
+		CloseCallback:       func() {},
+		scheme:              scheme,
+	}
+}
+
+// Resolver is also a resolver builder.
+// It's build() function always returns itself.
+type Resolver struct {
+	// BuildCallback is called when the Build method is called.  Must not be
+	// nil.  Must not be changed after the resolver may be built.
+	BuildCallback func(resolver.Target, resolver.ClientConn, resolver.BuildOptions)
+	// UpdateStateCallback is called when the UpdateState method is called on
+	// the resolver.  The value passed as argument to this callback is the value
+	// returned by the resolver.ClientConn.  Must not be nil.  Must not be
+	// changed after the resolver may be built.
+	UpdateStateCallback func(err error)
+	// ResolveNowCallback is called when the ResolveNow method is called on the
+	// resolver.  Must not be nil.  Must not be changed after the resolver may
+	// be built.
+	ResolveNowCallback func(resolver.ResolveNowOptions)
+	// CloseCallback is called when the Close method is called.  Must not be
+	// nil.  Must not be changed after the resolver may be built.
+	CloseCallback func()
+	scheme        string
+
+	// Fields actually belong to the resolver.
+	// Guards access to below fields.
+	mu sync.Mutex
+	cc resolver.ClientConn
+	// Storing the most recent state update makes this resolver resilient to
+	// restarts, which is possible with channel idleness.
+	lastSeenState *resolver.State
+}
+
+// InitialState adds initial state to the resolver so that UpdateState doesn't
+// need to be explicitly called after Dial.
+func (r *Resolver) InitialState(s resolver.State) {
+	r.lastSeenState = &s
+}
+
+// Build returns itself for Resolver, because it's both a builder and a resolver.
+func (r *Resolver) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	// Call BuildCallback after locking to avoid a race when UpdateState or CC
+	// is called before Build returns.
+	r.BuildCallback(target, cc, opts)
+	r.cc = cc
+	if r.lastSeenState != nil {
+		err := r.cc.UpdateState(*r.lastSeenState)
+		go r.UpdateStateCallback(err)
+	}
+	return r, nil
+}
+
+// Scheme returns the manual resolver's scheme.
+func (r *Resolver) Scheme() string {
+	return r.scheme
+}
+
+// ResolveNow is a noop for Resolver.
+func (r *Resolver) ResolveNow(o resolver.ResolveNowOptions) {
+	r.ResolveNowCallback(o)
+}
+
+// Close is a noop for Resolver.
+func (r *Resolver) Close() {
+	r.CloseCallback()
+}
+
+// UpdateState calls UpdateState(s) on the channel.  If the resolver has not
+// been Built before, this instead sets the initial state of the resolver, like
+// InitialState.
+func (r *Resolver) UpdateState(s resolver.State) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.lastSeenState = &s
+	if r.cc == nil {
+		return
+	}
+	err := r.cc.UpdateState(s)
+	r.UpdateStateCallback(err)
+}
+
+// CC returns r's ClientConn when r was last Built.  Panics if the resolver has
+// not been Built before.
+func (r *Resolver) CC() resolver.ClientConn {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.cc == nil {
+		panic("Manual resolver instance has not yet been built.")
+	}
+	return r.cc
+}
diff --git a/vendor/google.golang.org/grpc/resolver/map.go b/vendor/google.golang.org/grpc/resolver/map.go
new file mode 100644
index 0000000..c3c15ac
--- /dev/null
+++ b/vendor/google.golang.org/grpc/resolver/map.go
@@ -0,0 +1,247 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package resolver
+
+import (
+	"encoding/base64"
+	"sort"
+	"strings"
+)
+
+type addressMapEntry[T any] struct {
+	addr  Address
+	value T
+}
+
+// AddressMap is an AddressMapV2[any].  It will be deleted in an upcoming
+// release of grpc-go.
+//
+// Deprecated: use the generic AddressMapV2 type instead.
+type AddressMap = AddressMapV2[any]
+
+// AddressMapV2 is a map of addresses to arbitrary values taking into account
+// Attributes.  BalancerAttributes are ignored, as are Metadata and Type.
+// Multiple accesses may not be performed concurrently.  Must be created via
+// NewAddressMap; do not construct directly.
+type AddressMapV2[T any] struct {
+	// The underlying map is keyed by an Address with fields that we don't care
+	// about being set to their zero values. The only fields that we care about
+	// are `Addr`, `ServerName` and `Attributes`. Since we need to be able to
+	// distinguish between addresses with same `Addr` and `ServerName`, but
+	// different `Attributes`, we cannot store the `Attributes` in the map key.
+	//
+	// The comparison operation for structs work as follows:
+	//  Struct values are comparable if all their fields are comparable. Two
+	//  struct values are equal if their corresponding non-blank fields are equal.
+	//
+	// The value type of the map contains a slice of addresses which match the key
+	// in their `Addr` and `ServerName` fields and contain the corresponding value
+	// associated with them.
+	m map[Address]addressMapEntryList[T]
+}
+
+func toMapKey(addr *Address) Address {
+	return Address{Addr: addr.Addr, ServerName: addr.ServerName}
+}
+
+type addressMapEntryList[T any] []*addressMapEntry[T]
+
+// NewAddressMap creates a new AddressMapV2[any].
+//
+// Deprecated: use the generic NewAddressMapV2 constructor instead.
+func NewAddressMap() *AddressMap {
+	return NewAddressMapV2[any]()
+}
+
+// NewAddressMapV2 creates a new AddressMapV2.
+func NewAddressMapV2[T any]() *AddressMapV2[T] {
+	return &AddressMapV2[T]{m: make(map[Address]addressMapEntryList[T])}
+}
+
+// find returns the index of addr in the addressMapEntry slice, or -1 if not
+// present.
+func (l addressMapEntryList[T]) find(addr Address) int {
+	for i, entry := range l {
+		// Attributes are the only thing to match on here, since `Addr` and
+		// `ServerName` are already equal.
+		if entry.addr.Attributes.Equal(addr.Attributes) {
+			return i
+		}
+	}
+	return -1
+}
+
+// Get returns the value for the address in the map, if present.
+func (a *AddressMapV2[T]) Get(addr Address) (value T, ok bool) {
+	addrKey := toMapKey(&addr)
+	entryList := a.m[addrKey]
+	if entry := entryList.find(addr); entry != -1 {
+		return entryList[entry].value, true
+	}
+	return value, false
+}
+
+// Set updates or adds the value to the address in the map.
+func (a *AddressMapV2[T]) Set(addr Address, value T) {
+	addrKey := toMapKey(&addr)
+	entryList := a.m[addrKey]
+	if entry := entryList.find(addr); entry != -1 {
+		entryList[entry].value = value
+		return
+	}
+	a.m[addrKey] = append(entryList, &addressMapEntry[T]{addr: addr, value: value})
+}
+
+// Delete removes addr from the map.
+func (a *AddressMapV2[T]) Delete(addr Address) {
+	addrKey := toMapKey(&addr)
+	entryList := a.m[addrKey]
+	entry := entryList.find(addr)
+	if entry == -1 {
+		return
+	}
+	if len(entryList) == 1 {
+		entryList = nil
+	} else {
+		copy(entryList[entry:], entryList[entry+1:])
+		entryList = entryList[:len(entryList)-1]
+	}
+	a.m[addrKey] = entryList
+}
+
+// Len returns the number of entries in the map.
+func (a *AddressMapV2[T]) Len() int {
+	ret := 0
+	for _, entryList := range a.m {
+		ret += len(entryList)
+	}
+	return ret
+}
+
+// Keys returns a slice of all current map keys.
+func (a *AddressMapV2[T]) Keys() []Address {
+	ret := make([]Address, 0, a.Len())
+	for _, entryList := range a.m {
+		for _, entry := range entryList {
+			ret = append(ret, entry.addr)
+		}
+	}
+	return ret
+}
+
+// Values returns a slice of all current map values.
+func (a *AddressMapV2[T]) Values() []T {
+	ret := make([]T, 0, a.Len())
+	for _, entryList := range a.m {
+		for _, entry := range entryList {
+			ret = append(ret, entry.value)
+		}
+	}
+	return ret
+}
+
+type endpointMapKey string
+
+// EndpointMap is a map of endpoints to arbitrary values keyed on only the
+// unordered set of address strings within an endpoint. This map is not thread
+// safe, thus it is unsafe to access concurrently. Must be created via
+// NewEndpointMap; do not construct directly.
+type EndpointMap[T any] struct {
+	endpoints map[endpointMapKey]endpointData[T]
+}
+
+type endpointData[T any] struct {
+	// decodedKey stores the original key to avoid decoding when iterating on
+	// EndpointMap keys.
+	decodedKey Endpoint
+	value      T
+}
+
+// NewEndpointMap creates a new EndpointMap.
+func NewEndpointMap[T any]() *EndpointMap[T] {
+	return &EndpointMap[T]{
+		endpoints: make(map[endpointMapKey]endpointData[T]),
+	}
+}
+
+// encodeEndpoint returns a string that uniquely identifies the unordered set of
+// addresses within an endpoint.
+func encodeEndpoint(e Endpoint) endpointMapKey {
+	addrs := make([]string, 0, len(e.Addresses))
+	// base64 encoding the address strings restricts the characters present
+	// within the strings. This allows us to use a delimiter without the need of
+	// escape characters.
+	for _, addr := range e.Addresses {
+		addrs = append(addrs, base64.StdEncoding.EncodeToString([]byte(addr.Addr)))
+	}
+	sort.Strings(addrs)
+	// " " should not appear in base64 encoded strings.
+	return endpointMapKey(strings.Join(addrs, " "))
+}
+
+// Get returns the value for the address in the map, if present.
+func (em *EndpointMap[T]) Get(e Endpoint) (value T, ok bool) {
+	val, found := em.endpoints[encodeEndpoint(e)]
+	if found {
+		return val.value, true
+	}
+	return value, false
+}
+
+// Set updates or adds the value to the address in the map.
+func (em *EndpointMap[T]) Set(e Endpoint, value T) {
+	en := encodeEndpoint(e)
+	em.endpoints[en] = endpointData[T]{
+		decodedKey: Endpoint{Addresses: e.Addresses},
+		value:      value,
+	}
+}
+
+// Len returns the number of entries in the map.
+func (em *EndpointMap[T]) Len() int {
+	return len(em.endpoints)
+}
+
+// Keys returns a slice of all current map keys, as endpoints specifying the
+// addresses present in the endpoint keys, in which uniqueness is determined by
+// the unordered set of addresses. Thus, endpoint information returned is not
+// the full endpoint data (drops duplicated addresses and attributes) but can be
+// used for EndpointMap accesses.
+func (em *EndpointMap[T]) Keys() []Endpoint {
+	ret := make([]Endpoint, 0, len(em.endpoints))
+	for _, en := range em.endpoints {
+		ret = append(ret, en.decodedKey)
+	}
+	return ret
+}
+
+// Values returns a slice of all current map values.
+func (em *EndpointMap[T]) Values() []T {
+	ret := make([]T, 0, len(em.endpoints))
+	for _, val := range em.endpoints {
+		ret = append(ret, val.value)
+	}
+	return ret
+}
+
+// Delete removes the specified endpoint from the map.
+func (em *EndpointMap[T]) Delete(e Endpoint) {
+	en := encodeEndpoint(e)
+	delete(em.endpoints, en)
+}
diff --git a/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go b/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go
deleted file mode 100644
index c8a0c3d..0000000
--- a/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- *
- * Copyright 2017 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-// Package passthrough implements a pass-through resolver. It sends the target
-// name without scheme back to gRPC as resolved address.
-//
-// Deprecated: this package is imported by grpc and should not need to be
-// imported directly by users.
-package passthrough
-
-import _ "google.golang.org/grpc/internal/resolver/passthrough" // import for side effects after package was moved
diff --git a/vendor/google.golang.org/grpc/resolver/resolver.go b/vendor/google.golang.org/grpc/resolver/resolver.go
index 4c5423b..8e6af95 100644
--- a/vendor/google.golang.org/grpc/resolver/resolver.go
+++ b/vendor/google.golang.org/grpc/resolver/resolver.go
@@ -22,9 +22,16 @@
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"net"
+	"net/url"
+	"strings"
 
+	"google.golang.org/grpc/attributes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/experimental/stats"
+	"google.golang.org/grpc/internal"
 	"google.golang.org/grpc/serviceconfig"
 )
 
@@ -37,8 +44,9 @@
 
 // TODO(bar) install dns resolver in init(){}.
 
-// Register registers the resolver builder to the resolver map. b.Scheme will be
-// used as the scheme registered with this builder.
+// Register registers the resolver builder to the resolver map. b.Scheme will
+// be used as the scheme registered with this builder. The registry is case
+// sensitive, and schemes should not contain any uppercase characters.
 //
 // NOTE: this function must only be called during initialization time (i.e. in
 // an init() function), and is not thread-safe. If multiple Resolvers are
@@ -58,57 +66,92 @@
 }
 
 // SetDefaultScheme sets the default scheme that will be used. The default
-// default scheme is "passthrough".
+// scheme is initially set to "passthrough".
 //
 // NOTE: this function must only be called during initialization time (i.e. in
 // an init() function), and is not thread-safe. The scheme set last overrides
 // previously set values.
 func SetDefaultScheme(scheme string) {
 	defaultScheme = scheme
+	internal.UserSetDefaultScheme = true
 }
 
-// GetDefaultScheme gets the default scheme that will be used.
+// GetDefaultScheme gets the default scheme that will be used by grpc.Dial.  If
+// SetDefaultScheme is never called, the default scheme used by grpc.NewClient is "dns" instead.
 func GetDefaultScheme() string {
 	return defaultScheme
 }
 
-// AddressType indicates the address type returned by name resolution.
-type AddressType uint8
-
-const (
-	// Backend indicates the address is for a backend server.
-	Backend AddressType = iota
-	// GRPCLB indicates the address is for a grpclb load balancer.
-	GRPCLB
-)
-
 // Address represents a server the client connects to.
-// This is the EXPERIMENTAL API and may be changed or extended in the future.
+//
+// # Experimental
+//
+// Notice: This type is EXPERIMENTAL and may be changed or removed in a
+// later release.
 type Address struct {
 	// Addr is the server address on which a connection will be established.
 	Addr string
-	// Type is the type of this address.
-	Type AddressType
+
 	// ServerName is the name of this address.
 	// If non-empty, the ServerName is used as the transport certification authority for
 	// the address, instead of the hostname from the Dial target string. In most cases,
 	// this should not be set.
 	//
-	// If Type is GRPCLB, ServerName should be the name of the remote load
-	// balancer, not the name of the backend.
-	//
 	// WARNING: ServerName must only be populated with trusted values. It
 	// is insecure to populate it with data from untrusted inputs since untrusted
 	// values could be used to bypass the authority checks performed by TLS.
 	ServerName string
+
+	// Attributes contains arbitrary data about this address intended for
+	// consumption by the SubConn.
+	Attributes *attributes.Attributes
+
+	// BalancerAttributes contains arbitrary data about this address intended
+	// for consumption by the LB policy.  These attributes do not affect SubConn
+	// creation, connection establishment, handshaking, etc.
+	//
+	// Deprecated: when an Address is inside an Endpoint, this field should not
+	// be used, and it will eventually be removed entirely.
+	BalancerAttributes *attributes.Attributes
+
 	// Metadata is the information associated with Addr, which may be used
 	// to make load balancing decision.
-	Metadata interface{}
+	//
+	// Deprecated: use Attributes instead.
+	Metadata any
 }
 
-// BuildOption includes additional information for the builder to create
+// Equal returns whether a and o are identical.  Metadata is compared directly,
+// not with any recursive introspection.
+//
+// This method compares all fields of the address. When used to tell apart
+// addresses during subchannel creation or connection establishment, it might be
+// more appropriate for the caller to implement custom equality logic.
+func (a Address) Equal(o Address) bool {
+	return a.Addr == o.Addr && a.ServerName == o.ServerName &&
+		a.Attributes.Equal(o.Attributes) &&
+		a.BalancerAttributes.Equal(o.BalancerAttributes) &&
+		a.Metadata == o.Metadata
+}
+
+// String returns JSON formatted string representation of the address.
+func (a Address) String() string {
+	var sb strings.Builder
+	sb.WriteString(fmt.Sprintf("{Addr: %q, ", a.Addr))
+	sb.WriteString(fmt.Sprintf("ServerName: %q, ", a.ServerName))
+	if a.Attributes != nil {
+		sb.WriteString(fmt.Sprintf("Attributes: %v, ", a.Attributes.String()))
+	}
+	if a.BalancerAttributes != nil {
+		sb.WriteString(fmt.Sprintf("BalancerAttributes: %v", a.BalancerAttributes.String()))
+	}
+	sb.WriteString("}")
+	return sb.String()
+}
+
+// BuildOptions includes additional information for the builder to create
 // the resolver.
-type BuildOption struct {
+type BuildOptions struct {
 	// DisableServiceConfig indicates whether a resolver implementation should
 	// fetch service config data.
 	DisableServiceConfig bool
@@ -130,17 +173,52 @@
 	// field. In most cases though, it is not appropriate, and this field may
 	// be ignored.
 	Dialer func(context.Context, string) (net.Conn, error)
+	// Authority is the effective authority of the clientconn for which the
+	// resolver is built.
+	Authority string
+	// MetricsRecorder is the metrics recorder to do recording.
+	MetricsRecorder stats.MetricsRecorder
+}
+
+// An Endpoint is one network endpoint, or server, which may have multiple
+// addresses with which it can be accessed.
+type Endpoint struct {
+	// Addresses contains a list of addresses used to access this endpoint.
+	Addresses []Address
+
+	// Attributes contains arbitrary data about this endpoint intended for
+	// consumption by the LB policy.
+	Attributes *attributes.Attributes
 }
 
 // State contains the current Resolver state relevant to the ClientConn.
 type State struct {
 	// Addresses is the latest set of resolved addresses for the target.
+	//
+	// If a resolver sets Addresses but does not set Endpoints, one Endpoint
+	// will be created for each Address before the State is passed to the LB
+	// policy.  The BalancerAttributes of each entry in Addresses will be set
+	// in Endpoints.Attributes, and be cleared in the Endpoint's Address's
+	// BalancerAttributes.
+	//
+	// Soon, Addresses will be deprecated and replaced fully by Endpoints.
 	Addresses []Address
 
+	// Endpoints is the latest set of resolved endpoints for the target.
+	//
+	// If a resolver produces a State containing Endpoints but not Addresses,
+	// it must take care to ensure the LB policies it selects will support
+	// Endpoints.
+	Endpoints []Endpoint
+
 	// ServiceConfig contains the result from parsing the latest service
 	// config.  If it is nil, it indicates no service config is present or the
 	// resolver does not provide service configs.
 	ServiceConfig *serviceconfig.ParseResult
+
+	// Attributes contains arbitrary data about the resolver intended for
+	// consumption by the load balancing policy.
+	Attributes *attributes.Attributes
 }
 
 // ClientConn contains the callbacks for resolver to notify any updates
@@ -152,10 +230,19 @@
 // gRPC to add new methods to this interface.
 type ClientConn interface {
 	// UpdateState updates the state of the ClientConn appropriately.
-	UpdateState(State)
+	//
+	// If an error is returned, the resolver should try to resolve the
+	// target again. The resolver should use a backoff timer to prevent
+	// overloading the server with requests. If a resolver is certain that
+	// reresolving will not change the result, e.g. because it is
+	// a watch-based resolver, returned errors can be ignored.
+	//
+	// If the resolved State is the same as the last reported one, calling
+	// UpdateState can be omitted.
+	UpdateState(State) error
 	// ReportError notifies the ClientConn that the Resolver encountered an
-	// error.  The ClientConn will notify the load balancer and begin calling
-	// ResolveNow on the Resolver with exponential backoff.
+	// error. The ClientConn then forwards this error to the load balancing
+	// policy.
 	ReportError(error)
 	// NewAddress is called by resolver to notify ClientConn a new list
 	// of resolved addresses.
@@ -163,11 +250,6 @@
 	//
 	// Deprecated: Use UpdateState instead.
 	NewAddress(addresses []Address)
-	// NewServiceConfig is called by resolver to notify ClientConn a new
-	// service config. The service config should be provided as a json string.
-	//
-	// Deprecated: Use UpdateState instead.
-	NewServiceConfig(serviceConfig string)
 	// ParseServiceConfig parses the provided service config and returns an
 	// object that provides the parsed config.
 	ParseServiceConfig(serviceConfigJSON string) *serviceconfig.ParseResult
@@ -175,25 +257,43 @@
 
 // Target represents a target for gRPC, as specified in:
 // https://github.com/grpc/grpc/blob/master/doc/naming.md.
-// It is parsed from the target string that gets passed into Dial or DialContext by the user. And
-// grpc passes it to the resolver and the balancer.
+// It is parsed from the target string that gets passed into Dial or DialContext
+// by the user. And gRPC passes it to the resolver and the balancer.
 //
-// If the target follows the naming spec, and the parsed scheme is registered with grpc, we will
-// parse the target string according to the spec. e.g. "dns://some_authority/foo.bar" will be parsed
-// into &Target{Scheme: "dns", Authority: "some_authority", Endpoint: "foo.bar"}
-//
-// If the target does not contain a scheme, we will apply the default scheme, and set the Target to
-// be the full target string. e.g. "foo.bar" will be parsed into
-// &Target{Scheme: resolver.GetDefaultScheme(), Endpoint: "foo.bar"}.
-//
-// If the parsed scheme is not registered (i.e. no corresponding resolver available to resolve the
-// endpoint), we set the Scheme to be the default scheme, and set the Endpoint to be the full target
-// string. e.g. target string "unknown_scheme://authority/endpoint" will be parsed into
-// &Target{Scheme: resolver.GetDefaultScheme(), Endpoint: "unknown_scheme://authority/endpoint"}.
+// If the target follows the naming spec, and the parsed scheme is registered
+// with gRPC, we will parse the target string according to the spec. If the
+// target does not contain a scheme or if the parsed scheme is not registered
+// (i.e. no corresponding resolver available to resolve the endpoint), we will
+// apply the default scheme, and will attempt to reparse it.
 type Target struct {
-	Scheme    string
-	Authority string
-	Endpoint  string
+	// URL contains the parsed dial target with an optional default scheme added
+	// to it if the original dial target contained no scheme or contained an
+	// unregistered scheme. Any query params specified in the original dial
+	// target can be accessed from here.
+	URL url.URL
+}
+
+// Endpoint retrieves endpoint without leading "/" from either `URL.Path`
+// or `URL.Opaque`. The latter is used when the former is empty.
+func (t Target) Endpoint() string {
+	endpoint := t.URL.Path
+	if endpoint == "" {
+		endpoint = t.URL.Opaque
+	}
+	// For targets of the form "[scheme]://[authority]/endpoint, the endpoint
+	// value returned from url.Parse() contains a leading "/". Although this is
+	// in accordance with RFC 3986, we do not want to break existing resolver
+	// implementations which expect the endpoint without the leading "/". So, we
+	// end up stripping the leading "/" here. But this will result in an
+	// incorrect parsing for something like "unix:///path/to/socket". Since we
+	// own the "unix" resolver, we can workaround in the unix resolver by using
+	// the `URL` field.
+	return strings.TrimPrefix(endpoint, "/")
+}
+
+// String returns the canonical string representation of Target.
+func (t Target) String() string {
+	return t.URL.Scheme + "://" + t.URL.Host + "/" + t.Endpoint()
 }
 
 // Builder creates a resolver that will be used to watch name resolution updates.
@@ -202,14 +302,16 @@
 	//
 	// gRPC dial calls Build synchronously, and fails if the returned error is
 	// not nil.
-	Build(target Target, cc ClientConn, opts BuildOption) (Resolver, error)
-	// Scheme returns the scheme supported by this resolver.
-	// Scheme is defined at https://github.com/grpc/grpc/blob/master/doc/naming.md.
+	Build(target Target, cc ClientConn, opts BuildOptions) (Resolver, error)
+	// Scheme returns the scheme supported by this resolver.  Scheme is defined
+	// at https://github.com/grpc/grpc/blob/master/doc/naming.md.  The returned
+	// string should not contain uppercase characters, as they will not match
+	// the parsed target's scheme as defined in RFC 3986.
 	Scheme() string
 }
 
-// ResolveNowOption includes additional information for ResolveNow.
-type ResolveNowOption struct{}
+// ResolveNowOptions includes additional information for ResolveNow.
+type ResolveNowOptions struct{}
 
 // Resolver watches for the updates on the specified target.
 // Updates include address updates and service config updates.
@@ -218,14 +320,39 @@
 	// again. It's just a hint, resolver can ignore this if it's not necessary.
 	//
 	// It could be called multiple times concurrently.
-	ResolveNow(ResolveNowOption)
+	ResolveNow(ResolveNowOptions)
 	// Close closes the resolver.
 	Close()
 }
 
-// UnregisterForTesting removes the resolver builder with the given scheme from the
-// resolver map.
-// This function is for testing only.
-func UnregisterForTesting(scheme string) {
-	delete(m, scheme)
+// AuthorityOverrider is implemented by Builders that wish to override the
+// default authority for the ClientConn.
+// By default, the authority used is target.Endpoint().
+type AuthorityOverrider interface {
+	// OverrideAuthority returns the authority to use for a ClientConn with the
+	// given target. The implementation must generate it without blocking,
+	// typically in line, and must keep it unchanged.
+	//
+	// The returned string must be a valid ":authority" header value, i.e. be
+	// encoded according to
+	// [RFC3986](https://datatracker.ietf.org/doc/html/rfc3986#section-3.2) as
+	// necessary.
+	OverrideAuthority(Target) string
+}
+
+// ValidateEndpoints validates endpoints from a petiole policy's perspective.
+// Petiole policies should call this before calling into their children. See
+// [gRPC A61](https://github.com/grpc/proposal/blob/master/A61-IPv4-IPv6-dualstack-backends.md)
+// for details.
+func ValidateEndpoints(endpoints []Endpoint) error {
+	if len(endpoints) == 0 {
+		return errors.New("endpoints list is empty")
+	}
+
+	for _, endpoint := range endpoints {
+		for range endpoint.Addresses {
+			return nil
+		}
+	}
+	return errors.New("endpoints list contains no addresses")
 }