SignalR 6.x doesn't work with android il2cpp

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

(Building with Unity) SignalR 6.x (6.0.0, 6.0.1, 6.0.2) doesn’t work with android on IL2CPP. Works fine on windows il2cpp builds. Reverting to 5.x fixes the issue.

Expected Behavior

No response

Steps To Reproduce

• Create a unity project
• Add SignalR 6.x libraries
• Add a script that creates the hub connection, like this: var connection = new HubConnectionBuilder().WithUrl("http://localhost:5014/game").Build();
• Build with Il2CPP to android
• Exception (see below) is thrown when calling .Build()

Exceptions (if any)

03-06 12:42:04.721: E/Unity(28182): Parameter name: obj
03-06 12:42:04.721: E/Unity(28182):   at System.Threading.Monitor.ReliableEnterTimeout (System.Object obj, System.Int32 timeout, System.Boolean& lockTaken) [0x00000] in <00000000000000000000000000000000>:0 
03-06 12:42:04.721: E/Unity(28182):   at Microsoft.Extensions.DependencyInjection.DependencyInjectionEventSource.ServiceProviderBuilt (Microsoft.Extensions.DependencyInjection.ServiceProvider provider) [0x00000] in <00000000000000000000000000000000>:0 
03-06 12:42:04.721: E/Unity(28182):   at Microsoft.Extensions.DependencyInjection.ServiceProvider..ctor (System.Collections.Generic.ICollection`1[T] serviceDescriptors, Microsoft.Extensions.DependencyInjection.ServiceProviderOptions options) [0x00000] in <00000000000000000000000000000000>:0 
03-06 12:42:04.721: E/Unity(28182):   at Microsoft.Extensions.DependencyInjection.ServiceCollectionContainerBuilderExtensions.BuildServiceProvider (Microsoft.Extensions.DependencyInjection.IServiceCollection services, Microsoft.Extensions.DependencyInjection.ServiceProviderOptions options) [0x00000] in <00000000000000000000000000000000>:0 
03-06 12:42:04.721: E/Unity(28182):   at Mi```

### .NET Version

_No response_

### Anything else?

_No response_

[kolesnick]

I use this workaround to bypass that error:

var connection =
    new HubConnection(
        new HttpConnectionFactory(
            new OptionsWrapper<HttpConnectionOptions>(new HttpConnectionOptions
            {
                Transports = WebSockets,
                SkipNegotiation = true,
            }),
            new NullLoggerFactory()),
        new NewtonsoftJsonHubProtocol(),
        new UriEndPoint(new Uri(url)),
        new DummyServiceProvider(),
        new NullLoggerFactory(),
        new DefaultRetryPolicy())
    {
        ServerTimeout = Timeout,
    };

await connection.StartAsync();

Also 2 additional classes are needed:

internal sealed class DummyServiceProvider : IServiceProvider
{
    public object GetService(Type serviceType) => throw new NotSupportedException();
}

internal sealed class DefaultRetryPolicy : IRetryPolicy
{
    private static readonly TimeSpan?[] RetryDelays = { Zero, FromSeconds(2), FromSeconds(10), FromSeconds(30), null, };

    public TimeSpan? NextRetryDelay(RetryContext retryContext) => RetryDelays[retryContext.PreviousRetryCount];
}

[cristoferfnt]

Just tested the preview version (7.x), and the exception still occours. Will be using 5.0.17 for our project, but would like to use the newer version. When I have time, I’ll try to debug this more.