Redstone logger, which has unique id per request, to avoid interleaved request logs

redstone_logger_example.dart

Logger get logger => Zone.current[#logger];

Logger _initializeRequestLogger() {
  var uid = new Random().nextInt(1000);
  var logger = new Logger.detached("app:${uid}");
  logger.onRecord.listen(print);
  return logger;
}

@app.Route("/foo")
fooHandler() {
  return runZoned(() {
    logger.info("Started request");
    // we can do some handling even in a future
    return new Future(() => someFunction());
  }, zoneValues: {#logger: _initializeRequestLogger()});
}

void someFunction() {
  // And even here we can access logger we created in _iniitalizeRequestLogger();
  logger.info("Doing some work here");
}

// And the logger's output when our service is under heavy load will be something like:
//
// app:123: Started request
// app:345: Started request
// app:123: Doing some work here
// app:345: Doing some work here
//
// i.e. we will be able to distinguish logs from different requests, even despite the fact they happen simultaneously