AsyncR3 (variant of AsyncRx)

[fedeAlterio]

👋 R3Async - An Alternative Approach to Async Reactive Extensions

Hi Rx.NET community!

I wanted to share R3Async, an async reactive library that explores different design choices from Async.Rx. While I know you already have async support in Rx.NET (in preview), this is the async version of R3, which takes some different approaches compared to dotnet/reactive.

I'd really value your feedback on several design decisions (some inherited from R3, others specific to R3Async):

• ValueTask-based observers with CancellationToken baked directly into the core API (OnNextAsync(T value, CancellationToken cancellationToken))
• Awaited cancellation in operators like Switch - actually waiting for previous tasks to be fully canceled before starting the next one, rather than just initiating cancellation (which can lead to overlapping operations)
• Channel-based backpressure for ToAsyncEnumerable - requiring users to explicitly provide a channel factory (() => Channel.CreateBounded<T>(capacity)) to choose buffering semantics (bounded/unbounded/rendezvous)
• Resume-based error handling with OnErrorResumeAsync instead of terminating the stream on first error
• No ConfigureAwait(false) - preserving context flow by design (reasoning detailed in the README, with references to IAsyncEnumerable LINQ and Async context runtime#113567 and Synchronization Context Rx.Net Async #1967)
• ObserveOn concerns - I'm uncertain about scheduler abstractions in an async context. Since async/await already integrates with TaskScheduler and SynchronizationContext, I'm not sure if TimeProvider-based scheduling or custom schedulers would provide meaningful value here. Would love perspectives on this.

The README has detailed explanations and examples. The library is on NuGet with core operators implemented, though some features are still missing (BehaviorSubject, Publish, time-based operators like Throttle/Debounce, CombineLatest, etc.).

GitHub: https://github.com/fedeAlterio/R3Async
NuGet: https://www.nuget.org/packages/R3Async

Any thoughts, suggestions, or critiques would be greatly appreciated!