Asynchronously invoke this but expect to have the callback invoked every time a chunk of our request's body is written.
When the callback is invoked with the uploaded byte count equaling the message byte count, the call has completed.
weak_object is disposed during the call then this call will be cancelled. If the call is cancelled then the callback will be
invoked with an error state.
You may unref the call after calling this function since there is an internal reference, or you may unref in the callback.
a ProxyCallUploadCallback to invoke when a chunk of data was uploaded
The Object to weakly reference and tie the lifecycle to
data to pass to