Async notification for start channel message received for a given profile.
Functions using this handler:
Handler is used to notify peer role that a channel is being asked to be created. The handler receives a reference to the connection where the channel is being requested.
If peer agree to create the channel axl_true must be returned. Otherwise, axl_false must be used.
You can get the reference to the VortexChannel object in trasint to be created, by using vortex_connection_get_channel, but keep in mind the channel is it transit to be created. This is useful if you want to configure something on the channel.