def register_raw_inbound_handler(self, handler):
return self.event_handler.register_handler("<STR_LIT>", handler)<EOL>
Register a handler for all outgoing messages received from the Pebble. Transport framing is not included.
In most cases you should not need to use this; consider using :meth:`register_endpoint` instead.

:param handler: A callback to be called when any message is received.
:type handler: callable
:return: A handle that can be passed to :meth:`unregister_endpoint` to remove the handler.