onRequest - Can we add this to fetchResponseFromEventStream(...) as well

[phasmax]

At the moment onRequest is not called when fetchResponseFromEventStream() is called. I expected it to be called for any request, including streaming.

Can we either:

1. Also call onRequest on the request (POST) being sent in fetchResponseFromEventStream
   OR
2. Create a new handler, e.g. onEventStreamRequest() that can be used to manipulate the headers, body etc.