add wrapper

p2p/types.go

@@ -14,3 +14,17 @@ type Envelope struct {
 	Message   proto.Message // message payload
 	ChannelID byte
 }
+
+// Wrapper is a Protobuf message that can contain a variety of inner messages
+// (e.g. via oneof fields). If a Channel's message type implements Wrapper, the
+// Router will automatically wrap outbound messages and unwrap inbound messages,
+// such that reactors do not have to do this themselves.
+type Wrapper interface {
+	proto.Message
+
+	// Wrap will take a message and wrap it in this one if possible.
+	Wrap(proto.Message) error
+
+	// Unwrap will unwrap the inner message contained in this message.
+	Unwrap() (proto.Message, error)
+}