Summary: Send part of the response body every 100 ms if the client has set onreadystatechange. This
is done by using the same events as the iOS code and removing the callback that Android previously
used.
Reconsolidate iOS and Android implementations.
Closes#3772
(The previous commit was reverted)
public
Reviewed By: astreet
Differential Revision: D2658153
fb-gh-sync-id: b1a32d22db7cc2995c673edd31f4bbaf16ca36cb
532c9112b4