Issue: AspNetCoreSelfHost.IsStarted set before the server actually started for real

[davide-romanini]

From this code:

WireMock.Net/src/WireMock.Net/Owin/AspNetCoreSelfHost.cs

Lines 107 to 117 in 2075589

	IsStarted = true;
	#if NETSTANDARD1_3
	_logger.Info("WireMock.Net server using netstandard1.3");
	#elif NETSTANDARD2_0
	_logger.Info("WireMock.Net server using netstandard2.0");
	#elif NET46
	_logger.Info("WireMock.Net server using .net 4.6.1 or higher");
	#endif
	#if NETSTANDARD1_3
	_host.Run(_cts.Token);

is clear that IsStarted is set to true before the WebHost istance is running for real.

That causes sporadic "Connection refused" failures with code like this:

  var mockServer = FluentMockServer.Start();
  // we expect the server to be actually running and listening, but sometimes it's not still ready!
  await new HttpClient().SendAsync(new HttpRequestMessage(HttpMethod.Head, $"http:https://localhost:{mockServer.Ports[0]}"));

A better implementation could be listening for IApplicationLifetime events:

    IApplicationLifetime appLifeTime = (IApplicationLifetime)_host.Services.GetService(typeof(IApplicationLifetime));
    appLifeTime.ApplicationStarted.Register(() => {
        IsStarted = true;
    });