processMessage
Called to handle com.google.firebase.messaging.FirebaseMessagingService.onMessageReceived. The task should be finished before onMessageReceived(RemoteMessage message) is complete. Wait for the message to be complete by calling get() on the future. Don't call get() from the main thread: it blocks until the push is processed and can cause an ANR.
Return
A future.
Parameters
context
The application context.
message
The message.