How to use Dart's low level HttpClient with timeout and getting back the response text from the HttpClientResponse stream

howtousehttpclient_test.dart

import 'package:test/test.dart';
import 'dart:async';
import 'dart:io';
import 'dart:convert';

void main() {
  group("B1SL_LoginTestSeries", () {
    const ipAddress = "http://hana93srv:50001";
    const url = "/b1s/v1/";
    const user = "manager";
    const pwd ="123qwe";
    const companyDB ="SBODEMOUS";
    test("Login with HTTPClient",() async {
      try {
        final String postBody = '{"UserName":"${user}", "Password":"${pwd}", "CompanyDB":"${companyDB}"}';
        final String queryUrl = ipAddress + url + "Login";
        //final String queryUrl = "http://192.168.250.92:50001" + url + "Login";
        final HttpClient client = HttpClient()..connectionTimeout = Duration(seconds: 15);
        final HttpClientRequest request = await client.postUrl(Uri.parse(queryUrl));
        request.write(postBody);
        final HttpClientResponse response = await request.close();
        dynamic responseBodyText = await _getResponseBody(response);
        print(responseBodyText);
        expect(responseBodyText, isNotNull);
        expect(responseBodyText.isNotEmpty, isTrue);
      } catch(error,stackTrace) {
        print(error);
        print(stackTrace);
        expect(error,isNull);
      }
    });
  });
}
Future<dynamic> _getResponseBody(HttpClientResponse response) {
  StringBuffer responseBody = StringBuffer();
  Completer completer = Completer();
  response.transform(utf8.decoder).listen((String onData){
    responseBody.write(onData);
  }, onDone: ()=> completer.complete(responseBody.toString()));
  return completer.future;
}

I've spent a number of hours to experiment with using the brutally low level HttpClient and HttpClientResponse classes of dart:io just to be able to set timeout on my HTTP communication. Actually, connectionTimeout works, but instead of throwing a nice SocketException we get a NoSuchMethodError, possibly because of a bug in dart.io. The other option is to use Future's timeout, but I wasn't sure, if it may cause memory/resource leaks? The worst case would be that after a minute or so the network layer anyway kills the connection. So, I think Future timeout is the way to go, it is so clean and dead simple.