def fetch_scrollback(last_event_id)
      event_sent = false
      if last_event_id
        channels.each do |channel|
          channel.scrollback(since: last_event_id).each do |event|
            event_sent = true
            queue.push(event)
          end
        end
      end

      queue.push(Pubsubstub.heartbeat_event) unless event_sent
    end
def fetch_scrollback(last_event_id)
      event_sent = false
      if last_event_id
        channels.each do |channel|
          channel.scrollback(since: last_event_id).each do |event|
            event_sent = true
            queue.push(event)
          end
        end
      end

      queue.push(Pubsubstub.heartbeat_event) unless event_sent
    end
This method is not ideal as it doesn't guarantee order in case of multi-channel subscription