Called by the XmlStream when the stream has started.

This extends Authenticator.streamStarted to extract further stream headers from rootElement, optionally wait for stream features being received and then call initializeStream.

Function onFeatures Undocumented
def onFeatures(element): (source)
Undocumented
API Documentation for Twisted, generated by pydoctor at 2020-03-20 23:54:06.