An example of an unnecessary Completer usage in Dart

unnecessary_completer_1.dart

import 'dart:async';

final messageStorage = <String>[];

Future save(String message) {
  var completer = new Completer();
  new Future(() => messagesStorage.add(message)).then((_) => completer.complete());
  return completer.future;
}

Future<List<String>> getAll() {
  var completer = new Completer();
  new Future(() => messagesStorage).then((List<String> messages) => completer.complete(messages));
  return completer.future;
}

unnecessary_completer_2.dart

Future<bool> doServe() async {
  var c = new Completer();
  var httpServer = await HttpServer.bind(_SVhost, _SVport);

  // Connection monitor timer
  Timer monitor = new Timer.periodic(new Duration(seconds: 5), (_) {
    var connInfo = httpServer.connectionsInfo();
    log("Connections[${connInfo.total}]: active[${connInfo.active}] idle[${connInfo.idle}] closing[${connInfo.closing}]");
  });

  httpServer.listen((request) {
      log("Connection from [${request.connectionInfo.remoteAddress.toString()}] at [${request.connectionInfo.remotePort}]");
      request.response.writeln("Hello World!");
      request.response.close();
      c.complete(true);
    },
    onError: (e) {
      log.e("Error occured: ${e}");
    }
  );
  return c.future;
}