feat: introduce waitFor

[simone-sanfratello]

I'm proposing to introduce a waitFor method, as it is a very useful way to wait for a specific log message as it was an event, see this test case as an example https://github.com/fastify/fastify-http-proxy/pull/405/files#diff-b59655a410d4b510490ef7061e70dfd99b3f0b95473c0300376ff7c918d47d73R299

est('should call onDisconnect hook', async (t) => {
  const onDisconnect = () => {
    logger.info('onDisconnect called')
  }

  const wsReconnectOptions = {
    logs: true,
  }

  const { loggerSpy, logger, client } = await createServices({ t, wsReconnectOptions, wsHooks: { onDisconnect } })
  client.close()

  await waitForLogMessage(loggerSpy, 'onDisconnect called')
})

If you agree on it, I'm going for the implementation

[mcollina]

This would be a great idea, +1

[simone-sanfratello]

Cool, in this way we can get rid of plan

[simone-sanfratello]

I need to update the design, it does not work properly with concurrent calls, because of the event listen is added and removed