vendor/go.opentelemetry.io/otel/trace/trace.go - voltha-lib-go - Gitiles

 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0

 package trace // import "go.opentelemetry.io/otel/trace"

 import (
 	"encoding/json"
 )

 const (
 	// FlagsSampled is a bitmask with the sampled bit set. A SpanContext
 	// with the sampling bit set means the span is sampled.
 	FlagsSampled = TraceFlags(0x01)

 	errInvalidHexID errorConst = "trace-id and span-id can only contain [0-9a-f] characters, all lowercase"

 	errInvalidTraceIDLength errorConst = "hex encoded trace-id must have length equals to 32"
 	errNilTraceID           errorConst = "trace-id can't be all zero"

 	errInvalidSpanIDLength errorConst = "hex encoded span-id must have length equals to 16"
 	errNilSpanID           errorConst = "span-id can't be all zero"
 )

 type errorConst string

 func (e errorConst) Error() string {
 	return string(e)
 }

 // TraceID is a unique identity of a trace.
 // nolint:revive // revive complains about stutter of `trace.TraceID`.
 type TraceID [16]byte

 var (
 	nilTraceID TraceID
 	_          json.Marshaler = nilTraceID
 )

 // IsValid reports whether the trace TraceID is valid. A valid trace ID does
 // not consist of zeros only.
 func (t TraceID) IsValid() bool {
 	return t != nilTraceID
 }

 // MarshalJSON implements a custom marshal function to encode TraceID
 // as a hex string.
 func (t TraceID) MarshalJSON() ([]byte, error) {
 	b := [32 + 2]byte{0: '"', 33: '"'}
 	h := t.hexBytes()
 	copy(b[1:], h[:])
 	return b[:], nil
 }

 // String returns the hex string representation form of a TraceID.
 func (t TraceID) String() string {
 	h := t.hexBytes()
 	return string(h[:])
 }

 // hexBytes returns the hex string representation form of a TraceID.
 func (t TraceID) hexBytes() [32]byte {
 	return [32]byte{
 		hexLU[t[0x0]>>4], hexLU[t[0x0]&0xf],
 		hexLU[t[0x1]>>4], hexLU[t[0x1]&0xf],
 		hexLU[t[0x2]>>4], hexLU[t[0x2]&0xf],
 		hexLU[t[0x3]>>4], hexLU[t[0x3]&0xf],
 		hexLU[t[0x4]>>4], hexLU[t[0x4]&0xf],
 		hexLU[t[0x5]>>4], hexLU[t[0x5]&0xf],
 		hexLU[t[0x6]>>4], hexLU[t[0x6]&0xf],
 		hexLU[t[0x7]>>4], hexLU[t[0x7]&0xf],
 		hexLU[t[0x8]>>4], hexLU[t[0x8]&0xf],
 		hexLU[t[0x9]>>4], hexLU[t[0x9]&0xf],
 		hexLU[t[0xa]>>4], hexLU[t[0xa]&0xf],
 		hexLU[t[0xb]>>4], hexLU[t[0xb]&0xf],
 		hexLU[t[0xc]>>4], hexLU[t[0xc]&0xf],
 		hexLU[t[0xd]>>4], hexLU[t[0xd]&0xf],
 		hexLU[t[0xe]>>4], hexLU[t[0xe]&0xf],
 		hexLU[t[0xf]>>4], hexLU[t[0xf]&0xf],
 	}
 }

 // SpanID is a unique identity of a span in a trace.
 type SpanID [8]byte

 var (
 	nilSpanID SpanID
 	_         json.Marshaler = nilSpanID
 )

 // IsValid reports whether the SpanID is valid. A valid SpanID does not consist
 // of zeros only.
 func (s SpanID) IsValid() bool {
 	return s != nilSpanID
 }

 // MarshalJSON implements a custom marshal function to encode SpanID
 // as a hex string.
 func (s SpanID) MarshalJSON() ([]byte, error) {
 	b := [16 + 2]byte{0: '"', 17: '"'}
 	h := s.hexBytes()
 	copy(b[1:], h[:])
 	return b[:], nil
 }

 // String returns the hex string representation form of a SpanID.
 func (s SpanID) String() string {
 	b := s.hexBytes()
 	return string(b[:])
 }

 func (s SpanID) hexBytes() [16]byte {
 	return [16]byte{
 		hexLU[s[0]>>4], hexLU[s[0]&0xf],
 		hexLU[s[1]>>4], hexLU[s[1]&0xf],
 		hexLU[s[2]>>4], hexLU[s[2]&0xf],
 		hexLU[s[3]>>4], hexLU[s[3]&0xf],
 		hexLU[s[4]>>4], hexLU[s[4]&0xf],
 		hexLU[s[5]>>4], hexLU[s[5]&0xf],
 		hexLU[s[6]>>4], hexLU[s[6]&0xf],
 		hexLU[s[7]>>4], hexLU[s[7]&0xf],
 	}
 }

 // TraceIDFromHex returns a TraceID from a hex string if it is compliant with
 // the W3C trace-context specification.  See more at
 // https://www.w3.org/TR/trace-context/#trace-id
 // nolint:revive // revive complains about stutter of `trace.TraceIDFromHex`.
 func TraceIDFromHex(h string) (TraceID, error) {
 	if len(h) != 32 {
 		return [16]byte{}, errInvalidTraceIDLength
 	}
 	var b [16]byte
 	invalidMark := byte(0)
 	for i := 0; i < len(h); i += 4 {
 		b[i/2] = (hexRev[h[i]] << 4) | hexRev[h[i+1]]
 		b[i/2+1] = (hexRev[h[i+2]] << 4) | hexRev[h[i+3]]
 		invalidMark |= hexRev[h[i]] | hexRev[h[i+1]] | hexRev[h[i+2]] | hexRev[h[i+3]]
 	}
 	// If the upper 4 bits of any byte are not zero, there was an invalid hex
 	// character since invalid hex characters are 0xff in hexRev.
 	if invalidMark&0xf0 != 0 {
 		return [16]byte{}, errInvalidHexID
 	}
 	// If we didn't set any bits, then h was all zeros.
 	if invalidMark == 0 {
 		return [16]byte{}, errNilTraceID
 	}
 	return b, nil
 }

 // SpanIDFromHex returns a SpanID from a hex string if it is compliant
 // with the w3c trace-context specification.
 // See more at https://www.w3.org/TR/trace-context/#parent-id
 func SpanIDFromHex(h string) (SpanID, error) {
 	if len(h) != 16 {
 		return [8]byte{}, errInvalidSpanIDLength
 	}
 	var b [8]byte
 	invalidMark := byte(0)
 	for i := 0; i < len(h); i += 4 {
 		b[i/2] = (hexRev[h[i]] << 4) | hexRev[h[i+1]]
 		b[i/2+1] = (hexRev[h[i+2]] << 4) | hexRev[h[i+3]]
 		invalidMark |= hexRev[h[i]] | hexRev[h[i+1]] | hexRev[h[i+2]] | hexRev[h[i+3]]
 	}
 	// If the upper 4 bits of any byte are not zero, there was an invalid hex
 	// character since invalid hex characters are 0xff in hexRev.
 	if invalidMark&0xf0 != 0 {
 		return [8]byte{}, errInvalidHexID
 	}
 	// If we didn't set any bits, then h was all zeros.
 	if invalidMark == 0 {
 		return [8]byte{}, errNilSpanID
 	}
 	return b, nil
 }

 // TraceFlags contains flags that can be set on a SpanContext.
 type TraceFlags byte //nolint:revive // revive complains about stutter of `trace.TraceFlags`.

 // IsSampled reports whether the sampling bit is set in the TraceFlags.
 func (tf TraceFlags) IsSampled() bool {
 	return tf&FlagsSampled == FlagsSampled
 }

 // WithSampled sets the sampling bit in a new copy of the TraceFlags.
 func (tf TraceFlags) WithSampled(sampled bool) TraceFlags { // nolint:revive  // sampled is not a control flag.
 	if sampled {
 		return tf | FlagsSampled
 	}

 	return tf &^ FlagsSampled
 }

 // MarshalJSON implements a custom marshal function to encode TraceFlags
 // as a hex string.
 func (tf TraceFlags) MarshalJSON() ([]byte, error) {
 	b := [2 + 2]byte{0: '"', 3: '"'}
 	h := tf.hexBytes()
 	copy(b[1:], h[:])
 	return b[:], nil
 }

 // String returns the hex string representation form of TraceFlags.
 func (tf TraceFlags) String() string {
 	h := tf.hexBytes()
 	return string(h[:])
 }

 func (tf TraceFlags) hexBytes() [2]byte {
 	return [2]byte{hexLU[tf>>4], hexLU[tf&0xf]}
 }

 // SpanContextConfig contains mutable fields usable for constructing
 // an immutable SpanContext.
 type SpanContextConfig struct {
 	TraceID    TraceID
 	SpanID     SpanID
 	TraceFlags TraceFlags
 	TraceState TraceState
 	Remote     bool
 }

 // NewSpanContext constructs a SpanContext using values from the provided
 // SpanContextConfig.
 func NewSpanContext(config SpanContextConfig) SpanContext {
 	return SpanContext{
 		traceID:    config.TraceID,
 		spanID:     config.SpanID,
 		traceFlags: config.TraceFlags,
 		traceState: config.TraceState,
 		remote:     config.Remote,
 	}
 }

 // SpanContext contains identifying trace information about a Span.
 type SpanContext struct {
 	traceID    TraceID
 	spanID     SpanID
 	traceFlags TraceFlags
 	traceState TraceState
 	remote     bool
 }

 var _ json.Marshaler = SpanContext{}

 // IsValid reports whether the SpanContext is valid. A valid span context has a
 // valid TraceID and SpanID.
 func (sc SpanContext) IsValid() bool {
 	return sc.HasTraceID() && sc.HasSpanID()
 }

 // IsRemote reports whether the SpanContext represents a remotely-created Span.
 func (sc SpanContext) IsRemote() bool {
 	return sc.remote
 }

 // WithRemote returns a copy of sc with the Remote property set to remote.
 func (sc SpanContext) WithRemote(remote bool) SpanContext {
 	return SpanContext{
 		traceID:    sc.traceID,
 		spanID:     sc.spanID,
 		traceFlags: sc.traceFlags,
 		traceState: sc.traceState,
 		remote:     remote,
 	}
 }

 // TraceID returns the TraceID from the SpanContext.
 func (sc SpanContext) TraceID() TraceID {
 	return sc.traceID
 }

 // HasTraceID reports whether the SpanContext has a valid TraceID.
 func (sc SpanContext) HasTraceID() bool {
 	return sc.traceID.IsValid()
 }

 // WithTraceID returns a new SpanContext with the TraceID replaced.
 func (sc SpanContext) WithTraceID(traceID TraceID) SpanContext {
 	return SpanContext{
 		traceID:    traceID,
 		spanID:     sc.spanID,
 		traceFlags: sc.traceFlags,
 		traceState: sc.traceState,
 		remote:     sc.remote,
 	}
 }

 // SpanID returns the SpanID from the SpanContext.
 func (sc SpanContext) SpanID() SpanID {
 	return sc.spanID
 }

 // HasSpanID reports whether the SpanContext has a valid SpanID.
 func (sc SpanContext) HasSpanID() bool {
 	return sc.spanID.IsValid()
 }

 // WithSpanID returns a new SpanContext with the SpanID replaced.
 func (sc SpanContext) WithSpanID(spanID SpanID) SpanContext {
 	return SpanContext{
 		traceID:    sc.traceID,
 		spanID:     spanID,
 		traceFlags: sc.traceFlags,
 		traceState: sc.traceState,
 		remote:     sc.remote,
 	}
 }

 // TraceFlags returns the flags from the SpanContext.
 func (sc SpanContext) TraceFlags() TraceFlags {
 	return sc.traceFlags
 }

 // IsSampled reports whether the sampling bit is set in the SpanContext's TraceFlags.
 func (sc SpanContext) IsSampled() bool {
 	return sc.traceFlags.IsSampled()
 }

 // WithTraceFlags returns a new SpanContext with the TraceFlags replaced.
 func (sc SpanContext) WithTraceFlags(flags TraceFlags) SpanContext {
 	return SpanContext{
 		traceID:    sc.traceID,
 		spanID:     sc.spanID,
 		traceFlags: flags,
 		traceState: sc.traceState,
 		remote:     sc.remote,
 	}
 }

 // TraceState returns the TraceState from the SpanContext.
 func (sc SpanContext) TraceState() TraceState {
 	return sc.traceState
 }

 // WithTraceState returns a new SpanContext with the TraceState replaced.
 func (sc SpanContext) WithTraceState(state TraceState) SpanContext {
 	return SpanContext{
 		traceID:    sc.traceID,
 		spanID:     sc.spanID,
 		traceFlags: sc.traceFlags,
 		traceState: state,
 		remote:     sc.remote,
 	}
 }

 // Equal reports whether two SpanContext values are equal.
 func (sc SpanContext) Equal(other SpanContext) bool {
 	return sc.traceID == other.traceID &&
 		sc.spanID == other.spanID &&
 		sc.traceFlags == other.traceFlags &&
 		sc.traceState.String() == other.traceState.String() &&
 		sc.remote == other.remote
 }

 // MarshalJSON implements a custom marshal function to encode a SpanContext.
 func (sc SpanContext) MarshalJSON() ([]byte, error) {
 	return json.Marshal(SpanContextConfig{
 		TraceID:    sc.traceID,
 		SpanID:     sc.spanID,
 		TraceFlags: sc.traceFlags,
 		TraceState: sc.traceState,
 		Remote:     sc.remote,
 	})
 }
	// Copyright The OpenTelemetry Authors
	// SPDX-License-Identifier: Apache-2.0

	package trace // import "go.opentelemetry.io/otel/trace"

	import (
	"encoding/json"
	)

	const (
	// FlagsSampled is a bitmask with the sampled bit set. A SpanContext
	// with the sampling bit set means the span is sampled.
	FlagsSampled = TraceFlags(0x01)

	errInvalidHexID errorConst = "trace-id and span-id can only contain [0-9a-f] characters, all lowercase"

	errInvalidTraceIDLength errorConst = "hex encoded trace-id must have length equals to 32"
	errNilTraceID errorConst = "trace-id can't be all zero"

	errInvalidSpanIDLength errorConst = "hex encoded span-id must have length equals to 16"
	errNilSpanID errorConst = "span-id can't be all zero"
	)

	type errorConst string

	func (e errorConst) Error() string {
	return string(e)
	}

	// TraceID is a unique identity of a trace.
	// nolint:revive // revive complains about stutter of `trace.TraceID`.
	type TraceID [16]byte

	var (
	nilTraceID TraceID
	_ json.Marshaler = nilTraceID
	)

	// IsValid reports whether the trace TraceID is valid. A valid trace ID does
	// not consist of zeros only.
	func (t TraceID) IsValid() bool {
	return t != nilTraceID
	}

	// MarshalJSON implements a custom marshal function to encode TraceID
	// as a hex string.
	func (t TraceID) MarshalJSON() ([]byte, error) {
	b := [32 + 2]byte{0: '"', 33: '"'}
	h := t.hexBytes()
	copy(b[1:], h[:])
	return b[:], nil
	}

	// String returns the hex string representation form of a TraceID.
	func (t TraceID) String() string {
	h := t.hexBytes()
	return string(h[:])
	}

	// hexBytes returns the hex string representation form of a TraceID.
	func (t TraceID) hexBytes() [32]byte {
	return [32]byte{
	hexLU[t[0x0]>>4], hexLU[t[0x0]&0xf],
	hexLU[t[0x1]>>4], hexLU[t[0x1]&0xf],
	hexLU[t[0x2]>>4], hexLU[t[0x2]&0xf],
	hexLU[t[0x3]>>4], hexLU[t[0x3]&0xf],
	hexLU[t[0x4]>>4], hexLU[t[0x4]&0xf],
	hexLU[t[0x5]>>4], hexLU[t[0x5]&0xf],
	hexLU[t[0x6]>>4], hexLU[t[0x6]&0xf],
	hexLU[t[0x7]>>4], hexLU[t[0x7]&0xf],
	hexLU[t[0x8]>>4], hexLU[t[0x8]&0xf],
	hexLU[t[0x9]>>4], hexLU[t[0x9]&0xf],
	hexLU[t[0xa]>>4], hexLU[t[0xa]&0xf],
	hexLU[t[0xb]>>4], hexLU[t[0xb]&0xf],
	hexLU[t[0xc]>>4], hexLU[t[0xc]&0xf],
	hexLU[t[0xd]>>4], hexLU[t[0xd]&0xf],
	hexLU[t[0xe]>>4], hexLU[t[0xe]&0xf],
	hexLU[t[0xf]>>4], hexLU[t[0xf]&0xf],
	}
	}

	// SpanID is a unique identity of a span in a trace.
	type SpanID [8]byte

	var (
	nilSpanID SpanID
	_ json.Marshaler = nilSpanID
	)

	// IsValid reports whether the SpanID is valid. A valid SpanID does not consist
	// of zeros only.
	func (s SpanID) IsValid() bool {
	return s != nilSpanID
	}

	// MarshalJSON implements a custom marshal function to encode SpanID
	// as a hex string.
	func (s SpanID) MarshalJSON() ([]byte, error) {
	b := [16 + 2]byte{0: '"', 17: '"'}
	h := s.hexBytes()
	copy(b[1:], h[:])
	return b[:], nil
	}

	// String returns the hex string representation form of a SpanID.
	func (s SpanID) String() string {
	b := s.hexBytes()
	return string(b[:])
	}

	func (s SpanID) hexBytes() [16]byte {
	return [16]byte{
	hexLU[s[0]>>4], hexLU[s[0]&0xf],
	hexLU[s[1]>>4], hexLU[s[1]&0xf],
	hexLU[s[2]>>4], hexLU[s[2]&0xf],
	hexLU[s[3]>>4], hexLU[s[3]&0xf],
	hexLU[s[4]>>4], hexLU[s[4]&0xf],
	hexLU[s[5]>>4], hexLU[s[5]&0xf],
	hexLU[s[6]>>4], hexLU[s[6]&0xf],
	hexLU[s[7]>>4], hexLU[s[7]&0xf],
	}
	}

	// TraceIDFromHex returns a TraceID from a hex string if it is compliant with
	// the W3C trace-context specification. See more at
	// https://www.w3.org/TR/trace-context/#trace-id
	// nolint:revive // revive complains about stutter of `trace.TraceIDFromHex`.
	func TraceIDFromHex(h string) (TraceID, error) {
	if len(h) != 32 {
	return [16]byte{}, errInvalidTraceIDLength
	}
	var b [16]byte
	invalidMark := byte(0)
	for i := 0; i < len(h); i += 4 {
	b[i/2] = (hexRev[h[i]] << 4) \| hexRev[h[i+1]]
	b[i/2+1] = (hexRev[h[i+2]] << 4) \| hexRev[h[i+3]]
	invalidMark \|= hexRev[h[i]] \| hexRev[h[i+1]] \| hexRev[h[i+2]] \| hexRev[h[i+3]]
	}
	// If the upper 4 bits of any byte are not zero, there was an invalid hex
	// character since invalid hex characters are 0xff in hexRev.
	if invalidMark&0xf0 != 0 {
	return [16]byte{}, errInvalidHexID
	}
	// If we didn't set any bits, then h was all zeros.
	if invalidMark == 0 {
	return [16]byte{}, errNilTraceID
	}
	return b, nil
	}

	// SpanIDFromHex returns a SpanID from a hex string if it is compliant
	// with the w3c trace-context specification.
	// See more at https://www.w3.org/TR/trace-context/#parent-id
	func SpanIDFromHex(h string) (SpanID, error) {
	if len(h) != 16 {
	return [8]byte{}, errInvalidSpanIDLength
	}
	var b [8]byte
	invalidMark := byte(0)
	for i := 0; i < len(h); i += 4 {
	b[i/2] = (hexRev[h[i]] << 4) \| hexRev[h[i+1]]
	b[i/2+1] = (hexRev[h[i+2]] << 4) \| hexRev[h[i+3]]
	invalidMark \|= hexRev[h[i]] \| hexRev[h[i+1]] \| hexRev[h[i+2]] \| hexRev[h[i+3]]
	}
	// If the upper 4 bits of any byte are not zero, there was an invalid hex
	// character since invalid hex characters are 0xff in hexRev.
	if invalidMark&0xf0 != 0 {
	return [8]byte{}, errInvalidHexID
	}
	// If we didn't set any bits, then h was all zeros.
	if invalidMark == 0 {
	return [8]byte{}, errNilSpanID
	}
	return b, nil
	}

	// TraceFlags contains flags that can be set on a SpanContext.
	type TraceFlags byte //nolint:revive // revive complains about stutter of `trace.TraceFlags`.

	// IsSampled reports whether the sampling bit is set in the TraceFlags.
	func (tf TraceFlags) IsSampled() bool {
	return tf&FlagsSampled == FlagsSampled
	}

	// WithSampled sets the sampling bit in a new copy of the TraceFlags.
	func (tf TraceFlags) WithSampled(sampled bool) TraceFlags { // nolint:revive // sampled is not a control flag.
	if sampled {
	return tf \| FlagsSampled
	}

	return tf &^ FlagsSampled
	}

	// MarshalJSON implements a custom marshal function to encode TraceFlags
	// as a hex string.
	func (tf TraceFlags) MarshalJSON() ([]byte, error) {
	b := [2 + 2]byte{0: '"', 3: '"'}
	h := tf.hexBytes()
	copy(b[1:], h[:])
	return b[:], nil
	}

	// String returns the hex string representation form of TraceFlags.
	func (tf TraceFlags) String() string {
	h := tf.hexBytes()
	return string(h[:])
	}

	func (tf TraceFlags) hexBytes() [2]byte {
	return [2]byte{hexLU[tf>>4], hexLU[tf&0xf]}
	}

	// SpanContextConfig contains mutable fields usable for constructing
	// an immutable SpanContext.
	type SpanContextConfig struct {
	TraceID TraceID
	SpanID SpanID
	TraceFlags TraceFlags
	TraceState TraceState
	Remote bool
	}

	// NewSpanContext constructs a SpanContext using values from the provided
	// SpanContextConfig.
	func NewSpanContext(config SpanContextConfig) SpanContext {
	return SpanContext{
	traceID: config.TraceID,
	spanID: config.SpanID,
	traceFlags: config.TraceFlags,
	traceState: config.TraceState,
	remote: config.Remote,
	}
	}

	// SpanContext contains identifying trace information about a Span.
	type SpanContext struct {
	traceID TraceID
	spanID SpanID
	traceFlags TraceFlags
	traceState TraceState
	remote bool
	}

	var _ json.Marshaler = SpanContext{}

	// IsValid reports whether the SpanContext is valid. A valid span context has a
	// valid TraceID and SpanID.
	func (sc SpanContext) IsValid() bool {
	return sc.HasTraceID() && sc.HasSpanID()
	}

	// IsRemote reports whether the SpanContext represents a remotely-created Span.
	func (sc SpanContext) IsRemote() bool {
	return sc.remote
	}

	// WithRemote returns a copy of sc with the Remote property set to remote.
	func (sc SpanContext) WithRemote(remote bool) SpanContext {
	return SpanContext{
	traceID: sc.traceID,
	spanID: sc.spanID,
	traceFlags: sc.traceFlags,
	traceState: sc.traceState,
	remote: remote,
	}
	}

	// TraceID returns the TraceID from the SpanContext.
	func (sc SpanContext) TraceID() TraceID {
	return sc.traceID
	}

	// HasTraceID reports whether the SpanContext has a valid TraceID.
	func (sc SpanContext) HasTraceID() bool {
	return sc.traceID.IsValid()
	}

	// WithTraceID returns a new SpanContext with the TraceID replaced.
	func (sc SpanContext) WithTraceID(traceID TraceID) SpanContext {
	return SpanContext{
	traceID: traceID,
	spanID: sc.spanID,
	traceFlags: sc.traceFlags,
	traceState: sc.traceState,
	remote: sc.remote,
	}
	}

	// SpanID returns the SpanID from the SpanContext.
	func (sc SpanContext) SpanID() SpanID {
	return sc.spanID
	}

	// HasSpanID reports whether the SpanContext has a valid SpanID.
	func (sc SpanContext) HasSpanID() bool {
	return sc.spanID.IsValid()
	}

	// WithSpanID returns a new SpanContext with the SpanID replaced.
	func (sc SpanContext) WithSpanID(spanID SpanID) SpanContext {
	return SpanContext{
	traceID: sc.traceID,
	spanID: spanID,
	traceFlags: sc.traceFlags,
	traceState: sc.traceState,
	remote: sc.remote,
	}
	}

	// TraceFlags returns the flags from the SpanContext.
	func (sc SpanContext) TraceFlags() TraceFlags {
	return sc.traceFlags
	}

	// IsSampled reports whether the sampling bit is set in the SpanContext's TraceFlags.
	func (sc SpanContext) IsSampled() bool {
	return sc.traceFlags.IsSampled()
	}

	// WithTraceFlags returns a new SpanContext with the TraceFlags replaced.
	func (sc SpanContext) WithTraceFlags(flags TraceFlags) SpanContext {
	return SpanContext{
	traceID: sc.traceID,
	spanID: sc.spanID,
	traceFlags: flags,
	traceState: sc.traceState,
	remote: sc.remote,
	}
	}

	// TraceState returns the TraceState from the SpanContext.
	func (sc SpanContext) TraceState() TraceState {
	return sc.traceState
	}

	// WithTraceState returns a new SpanContext with the TraceState replaced.
	func (sc SpanContext) WithTraceState(state TraceState) SpanContext {
	return SpanContext{
	traceID: sc.traceID,
	spanID: sc.spanID,
	traceFlags: sc.traceFlags,
	traceState: state,
	remote: sc.remote,
	}
	}

	// Equal reports whether two SpanContext values are equal.
	func (sc SpanContext) Equal(other SpanContext) bool {
	return sc.traceID == other.traceID &&
	sc.spanID == other.spanID &&
	sc.traceFlags == other.traceFlags &&
	sc.traceState.String() == other.traceState.String() &&
	sc.remote == other.remote
	}

	// MarshalJSON implements a custom marshal function to encode a SpanContext.
	func (sc SpanContext) MarshalJSON() ([]byte, error) {
	return json.Marshal(SpanContextConfig{
	TraceID: sc.traceID,
	SpanID: sc.spanID,
	TraceFlags: sc.traceFlags,
	TraceState: sc.traceState,
	Remote: sc.remote,
	})
	}