Hi all, According to my observation, you can specify a URL or js content to render a page, for URL , then WeexSDK build a request for download the resource and pour into the engine to
render. But in most case, we need customize a request for downloading a resource, and we can setup our request userAgent and headers, our server can receive these header to customize response for a request from a device. As for this we can expose a `renderWithRequest` interface for WXSDKInstance, is this way convenient ? comments? please
