GREYUIWebViewDelegate makes all XMLHttpRequests synchronous

The GREYUIWebViewDelegate forces all XMLHttpRequests to be synchronous:
grey_ajaxListener.originalOpen.apply(this, [method, url, **false**, user, password]);

This causes failures in some scenarios which the sync api doesn't support, for example setting the responseType will result in the following error: "Synchronous HTTP(S) requests made from the window context cannot have XMLHttpRequest.responseType set".

Is it possible not to force XMLHTTPRequests to be sync? (perhaps adding an event listener tot he 'load' event and then doing grey_ajaxListener.updateStatus('completed'))