add the opentelemetry tracing (#908)

* add the opentelemetry tracing

* fix the error sampler config

* 添加stream的链路跟踪

* fix the error field name

core/opentelemetry/message.go

@@ -0,0 +1,34 @@
+package opentelemetry
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+	"google.golang.org/protobuf/proto"
+)
+
+var (
+	MessageSent     = messageType(RPCMessageTypeSent)
+	MessageReceived = messageType(RPCMessageTypeReceived)
+)
+
+type messageType attribute.KeyValue
+
+// Event adds an event of the messageType to the span associated with the
+// passed context with id and size (if message is a proto message).
+func (m messageType) Event(ctx context.Context, id int, message interface{}) {
+	span := trace.SpanFromContext(ctx)
+	if p, ok := message.(proto.Message); ok {
+		span.AddEvent("message", trace.WithAttributes(
+			attribute.KeyValue(m),
+			RPCMessageIDKey.Int(id),
+			RPCMessageUncompressedSizeKey.Int(proto.Size(p)),
+		))
+	} else {
+		span.AddEvent("message", trace.WithAttributes(
+			attribute.KeyValue(m),
+			RPCMessageIDKey.Int(id),
+		))
+	}
+}