diff --git a/lib/socket.js b/lib/socket.js
index <HASH>..<HASH> 100644
--- a/lib/socket.js
+++ b/lib/socket.js
@@ -248,6 +248,7 @@ Socket.prototype.ack = function(){
  */
 
 Socket.prototype.onack = function(packet){
+  debug('calling ack %s with %j', packet.id, packet.data);
   this.acks[packet.id].apply(this, packet.data);
   delete this.acks[packet.id];
 };
socket: added `onack` instrumentation