What if `Conn.wait` was modified to take a list of names.

```rb
def wait(*channels)
  channels.each do |chan|
    execute('LISTEN "' + chan + '"')
  end
  wait_for_notify(WAIT_TIME)
  channels.each do |chan|
    execute('UNLISTEN "' + chan + '"')
  end
  drain_notify
end
```