Ok, which app server sent the push message can be identified using the
arbitrary data fields in the message.
If one app sends simultaneous multiple
com.google.android.c2dm.intent.REGISTER intents (with same app_id and
a different sender_id) to request registration with C2DM for multiple
app servers, how to identify that a registration result received on
the app is for a particular app server?
The registration result com.google.android.c2dm.intent.REGISTRATION
seems to have only the "registration_id" extra. How can this result be
used to identify that it is for a particular app server?