Reworded comment

router/connection.go

@@ -181,9 +181,11 @@ func (conn *LocalConnection) log(args ...interface{}) {
 	log.Println(append(append([]interface{}{}, fmt.Sprintf("->[%s]:", conn.remote.Name)), args...)...)
 }
 
-// Send directly - not via the Actor queryLoop.
-// note that tcpSender is immutable and guaranteed to be set by the
-// time anybody can get hold of a ref to the Connection
+// Send directly, not via the Actor.  If it goes via the Actor we can
+// get a deadlock where LocalConnection is blocked talking to
+// LocalPeer and LocalPeer is blocked trying send a ProtocolMsg via
+// LocalConnection, and the channels are full in both directions so
+// nothing can proceed.
 func (conn *LocalConnection) SendProtocolMsg(m ProtocolMsg) {
 	if err := conn.sendProtocolMsg(m); err != nil {
 		conn.Shutdown(err)