For now only the same data channel messages that were already handled
are taken into account, but at a later point the missing messages
("speaking" and "stoppedSpeaking") could be added too.
Note that the thread used to handle the data channel messages has
changed; the EventBus subscriber mode was "MAIN", but as the messages
were posted from a DataChannel observer, which run in a worker thread
rather than in the main thread, the subscriber was executed in the main
thread rather than in the same thread as the poster. Due to this the
actions performed by the handler now must be explicitly run in the main
thread.
Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>
