Observable.FromAsync swallows errors

[fubar-coder]

Problem:

It seems that errors thrown from an async/await method are swallowed instead of being received by the subscriber.

Example:

var evt = new AutoResetEvent(false);
Observable.FromAsync(TestAsync)
    .Subscribe(
        _ => "Next".Dump(),
        ex => $"Error {ex}".Dump(),
        _ => { "Completed".Dump(); evt.Set(); });
evt.WaitOne();

async ValueTask TestAsync(CancellationToken ct)
{
    await Task.Delay(TimeSpan.FromMilliseconds(1));
    throw new InvalidOperationException();
}

Expected output:

Error ....etc...
Completed

Actual output:

Completed