split wrap into wrap / unwrap types

p2p/peer.go

@@ -420,7 +420,7 @@ func createMConnection(
 			"peer_id", string(p.ID()),
 			"chID", fmt.Sprintf("%#x", chID),
 		}
-		if w, ok := msg.(Wrapper); ok {
+		if w, ok := msg.(Unwrapper); ok {
 			msg, err = w.Unwrap()
 			if err != nil {
 				// TODO(williambanfield) add error log line.

p2p/types.go

@@ -19,12 +19,14 @@ type Envelope struct {
 // (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 {
+type Unwrapper 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)
 }
+
+type Wrapper interface {
+	// Wrap will take the underlying message and wrap it in its wrapper type.
+	Wrap() (proto.Message, error)
+}