SignalR never start on iOS using Xamarin Forms

Question

I'm trying to use SignalR in my Xamarin Forms project. It works perfectly when I'm using Android (device or simulator). But using the same code on iOS, it hangs at await hubConnection.StartAsync();

I'm using Visual Studio 2022. XAML hot reload is disabled. I've tried adding the System.Memory and System.Buffers IncludeAssets None fix.

Here's the code

public async Task StartObserving()
{
    Uri signalRUri = new Uri("a-valid-uri-string-here");
    string jwt = await SecureStorage.GetAsync(SecureStorageKeys.IdToken);

    HubConnection hubConnection = new HubConnectionBuilder()
        .WithUrl(
            signalRUri,
            options =>
            {
                options.AccessTokenProvider = () => Task.FromResult(jwt);
                options.WebSocketConfiguration = (clientWebSocketOptions) =>
                {
                    clientWebSocketOptions.RemoteCertificateValidationCallback = (object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) =>
                    {
                        return true;
                    };
                };
                options.HttpMessageHandlerFactory = (httpMessageHandler) =>
                {
                    if (httpMessageHandler is HttpClientHandler clientHandler)
                    {
                        clientHandler.ServerCertificateCustomValidationCallback = (HttpRequestMessage httpRequestMessage, X509Certificate2 certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) =>
                        {
                            return true;
                        };
                    }

                    return httpMessageHandler;
                };
            })
        .ConfigureLogging(logging =>
        {
            logging.SetMinimumLevel(LogLevel.Trace);
            logging.AddConsole();
        })
        .Build();

    hubConnection.On<string>(
        "Send",
        OnMessageReceivedFromSignalR);

    await hubConnection.StartAsync();
}

Here's the SignalR log

2022-03-23 13:21:01.453 MyApp.iOS[2581:54607] [40m[37mdbug[39m[22m[49m: Microsoft.AspNetCore.SignalR.Client.HubConnection[40] Registering handler for client method 'Send'.

2022-03-23 13:21:01.464 MyApp.iOS[2581:54607] [40m[37mtrce[39m[22m[49m: Microsoft.AspNetCore.SignalR.Client.HubConnection[42] Waiting on Connection Lock in StartAsyncInner (/_/src/SignalR/clients/csharp/Client.Core/src/HubConnection.cs:247).

2022-03-23 13:21:01.472 MyApp.iOS[2581:54607] [40m[37mtrce[39m[22m[49m: Microsoft.AspNetCore.SignalR.Client.HubConnection[80] The HubConnection is attempting to transition from the Disconnected state to the Connecting state.

2022-03-23 13:21:01.476 MyApp.iOS[2581:54607] [40m[37mdbug[39m[22m[49m: Microsoft.AspNetCore.SignalR.Client.HubConnection[41] Starting HubConnection.

2022-03-23 13:21:01.486 MyApp.iOS[2581:54607] [40m[37mdbug[39m[22m[49m: Microsoft.AspNetCore.Http.Connections.Client.HttpConnection[1] Starting HttpConnection.

2022-03-23 13:21:01.503 MyApp.iOS[2581:54607] [40m[37mdbug[39m[22m[49m: Microsoft.AspNetCore.Http.Connections.Client.HttpConnection[5] Skipping dispose, connection is already disposed.

2022-03-23 13:21:01.506 MyApp.iOS[2581:54607] [40m[37mtrce[39m[22m[49m: Microsoft.AspNetCore.SignalR.Client.HubConnection[80] The HubConnection is attempting to transition from the Connecting state to the Disconnected state.

2022-03-23 13:21:01.506 MyApp.iOS[2581:54607] [40m[37mtrce[39m[22m[49m: Microsoft.AspNetCore.SignalR.Client.HubConnection[20] Releasing Connection Lock in StartAsyncInner (/_/src/SignalR/clients/csharp/Client.Core/src/HubConnection.cs:280).

I'm getting the following Exception

System.MissingMethodException: Method not found: Microsoft.AspNetCore.Http.Connections.NegotiationResponse Microsoft.AspNetCore.Http.Connections.NegotiateProtocol.ParseResponse(System.ReadOnlySpan1) at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult].Start[TStateMachine] (TStateMachine& stateMachine) [0x0002c] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs:471 at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.NegotiateAsync (System.Uri url, System.Net.Http.HttpClient httpClient, Microsoft.Extensions.Logging.ILogger logger, System.Threading.CancellationToken cancellationToken) [0x0003d] in :0 at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.GetNegotiationResponseAsync (System.Uri uri, System.Threading.CancellationToken cancellationToken) [0x00011] in :0 at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.SelectAndStartTransport (Microsoft.AspNetCore.Connections.TransferFormat transferFormat, System.Threading.CancellationToken cancellationToken) [0x0017b] in :0 at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.StartAsyncCore (Microsoft.AspNetCore.Connections.TransferFormat transferFormat, System.Threading.CancellationToken cancellationToken) [0x00127] in :0 at System.Threading.Tasks.ForceAsyncAwaiter.GetResult () [0x0000c] in :0 at Microsoft.AspNetCore.Http.Connections.Client.HttpConnection.StartAsync (Microsoft.AspNetCore.Connections.TransferFormat transferFormat, System.Threading.CancellationToken cancellationToken) [0x00091] in :0 at Microsoft.AspNetCore.Http.Connections.Client.HttpConnectionFactory.ConnectAsync (System.Net.EndPoint endPoint, System.Threading.CancellationToken cancellationToken) [0x00114] in :0
at Microsoft.AspNetCore.Http.Connections.Client.HttpConnectionFactory.ConnectAsync (System.Net.EndPoint endPoint, System.Threading.CancellationToken cancellationToken) [0x001bf] in :0
at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncCore (System.Threading.CancellationToken cancellationToken) [0x000a9] in <22c2b3ef3848439db8bf52b72cbcab20>:0 at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncInner (System.Threading.CancellationToken cancellationToken) [0x001a3] in <22c2b3ef3848439db8bf52b72cbcab20>:0 at System.Threading.Tasks.ForceAsyncAwaiter.GetResult () [0x0000c] in <22c2b3ef3848439db8bf52b72cbcab20>:0 at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsync (System.Threading.CancellationToken cancellationToken) [0x00091] in <22c2b3ef3848439db8bf52b72cbcab20>:0 at MyApp.StartObserving () [0x0027b] in C:\Dev\MobileApp\MyApp\MyApp\Services\CacheService.cs:279

Answer 1

Well I had only half of the solution implemented.

What fixed it for me was adding this to BOTH the common AND iOS projects. Not only the common project.

<PackageReference Include="System.Buffers">
  <Version>4.5.1</Version>
  <IncludeAssets>none</IncludeAssets>      
</PackageReference>
<PackageReference Include="System.Memory">
  <Version>4.5.4</Version>
  <IncludeAssets>none</IncludeAssets>      
</PackageReference>