WASM: SynchronizationContext not set when processing input events

[appel1]

Describe the bug

When dispatching input events in BrowserInputHandler, Thread.SynchronizationContext is not set, it is null.

This makes binding to observables break.

System.InvalidOperationException: TaskScheduler_FromCurrentSynchronizationContext_NoCurrent
   at System.Threading.Tasks.SynchronizationContextTaskScheduler..ctor()
   at System.Threading.Tasks.TaskScheduler.FromCurrentSynchronizationContext()
   at Avalonia.Markup.Xaml.MarkupExtensions.CompiledBindings.TaskStreamPlugin`1[[System.String, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].Start(WeakReference`1 reference)
   at Avalonia.Data.Core.ExpressionNodes.StreamNode.OnSourceChanged(Object source, Exception dataValidationError)
   at Avalonia.Data.Core.ExpressionNodes.ExpressionNode.SetSource(Object source, Exception dataValidationError)

To Reproduce

Create a browser app that binds to a task property and the property value is created as a response to input.

Expected behavior

The bound view is updated when the bound task or observable completes.

Avalonia version

11.3.9

OS

WebAssembly

Additional context

AvaloniaApplication1.zip

[appel1]

Current workaround, which is a bit cumbersome, is to wrap the body of all event handlers for input events with this:

// In the browser Avalonia does not set the synchronization context for input events, so we need to ensure it is set.
using (AvaloniaSynchronizationContext.Ensure(Dispatcher.UIThread, DispatcherPriority.Default))
{
  // Actual event handler goes here
}