handleChannelEvent
Handles additional events:
NotificationMessageNewEvent - calls watch and adds the channel to the set.
NotificationRemovedFromChannelEvent - removes the channel from the set if a current user left.
NotificationAddedToChannelEvent - calls watch and adds the channel to the set if a current user was added.
Return
EventHandlingResult Result of handling.
Parameters
event
ChatEvent that may contain updates for the set of channels.
filter
FilterObject associated with the set of channels. Can be used to define the result of handling.