+
+type incomingTagsKey struct{}
+type outgoingTagsKey struct{}
+
+// SetTags attaches stats tagging data to the context, which will be sent in
+// the outgoing RPC with the header grpc-tags-bin. Subsequent calls to
+// SetTags will overwrite the values from earlier calls.
+//
+// NOTE: this is provided only for backward compatibility with existing clients
+// and will likely be removed in an upcoming release. New uses should transmit
+// this type of data using metadata with a different, non-reserved (i.e. does
+// not begin with "grpc-") header name.
+func SetTags(ctx context.Context, b []byte) context.Context {
+ return context.WithValue(ctx, outgoingTagsKey{}, b)
+}
+
+// Tags returns the tags from the context for the inbound RPC.
+//
+// NOTE: this is provided only for backward compatibility with existing clients
+// and will likely be removed in an upcoming release. New uses should transmit
+// this type of data using metadata with a different, non-reserved (i.e. does
+// not begin with "grpc-") header name.
+func Tags(ctx context.Context) []byte {
+ b, _ := ctx.Value(incomingTagsKey{}).([]byte)
+ return b
+}
+
+// SetIncomingTags attaches stats tagging data to the context, to be read by
+// the application (not sent in outgoing RPCs).
+//
+// This is intended for gRPC-internal use ONLY.
+func SetIncomingTags(ctx context.Context, b []byte) context.Context {
+ return context.WithValue(ctx, incomingTagsKey{}, b)
+}
+
+// OutgoingTags returns the tags from the context for the outbound RPC.
+//
+// This is intended for gRPC-internal use ONLY.
+func OutgoingTags(ctx context.Context) []byte {
+ b, _ := ctx.Value(outgoingTagsKey{}).([]byte)
+ return b
+}
+
+type incomingTraceKey struct{}
+type outgoingTraceKey struct{}
+
+// SetTrace attaches stats tagging data to the context, which will be sent in
+// the outgoing RPC with the header grpc-trace-bin. Subsequent calls to
+// SetTrace will overwrite the values from earlier calls.
+//
+// NOTE: this is provided only for backward compatibility with existing clients
+// and will likely be removed in an upcoming release. New uses should transmit
+// this type of data using metadata with a different, non-reserved (i.e. does
+// not begin with "grpc-") header name.
+func SetTrace(ctx context.Context, b []byte) context.Context {
+ return context.WithValue(ctx, outgoingTraceKey{}, b)
+}
+
+// Trace returns the trace from the context for the inbound RPC.
+//
+// NOTE: this is provided only for backward compatibility with existing clients
+// and will likely be removed in an upcoming release. New uses should transmit
+// this type of data using metadata with a different, non-reserved (i.e. does
+// not begin with "grpc-") header name.
+func Trace(ctx context.Context) []byte {
+ b, _ := ctx.Value(incomingTraceKey{}).([]byte)
+ return b
+}
+
+// SetIncomingTrace attaches stats tagging data to the context, to be read by
+// the application (not sent in outgoing RPCs). It is intended for
+// gRPC-internal use.
+func SetIncomingTrace(ctx context.Context, b []byte) context.Context {
+ return context.WithValue(ctx, incomingTraceKey{}, b)
+}
+
+// OutgoingTrace returns the trace from the context for the outbound RPC. It is
+// intended for gRPC-internal use.
+func OutgoingTrace(ctx context.Context) []byte {
+ b, _ := ctx.Value(outgoingTraceKey{}).([]byte)
+ return b
+}