code: function(){
                  // Remove the handler
                  var w = callerWindow || this;
                  un(w, "load", onLoad);
                  easyXDM.Fn.set(config.channel + "_load", _onLoad);
                  (function test(){
                      if (typeof w.contentWindow.sendMessage == "function") {
                          _onReady();
                      }
                      else {
                          setTimeout(test, 50);
                      }
                  }());
              }
docs: Set up the iframe that will be used for the transport