def process_leave(data)
      @state.update data['state'] if data.key? 'state'
      @timeline.update data['timeline'] if data.key? 'timeline'
    end
def process_leave(data)
      @state.update data['state'] if data.key? 'state'
      @timeline.update data['timeline'] if data.key? 'timeline'
    end
Process leave events for this room.
 @param data [Hash] Event data containing state and timeline events up
   until the point of leaving the room.