System.Threading.Channels.AsyncOperation<TSelf, TResult>
abstract class AsyncOperation<TSelf, TResult> : AsyncOperation<TSelf>, IValueTaskSource<TResult> where TSelf : AsyncOperation<TSelf, TResult>
public AsyncOperation(bool runContinuationsAsynchronously, CancellationToken cancellationToken = default, bool pooled = false, Action<object, CancellationToken> cancellationCallback = null)