namespace System.Reactive.Linq.ObservableImpl { internal sealed class AverageInt32Nullable : Producer<double?, AverageInt32Nullable._> { internal sealed class _ : Sink<double?>, IObserver<int?> { private long _sum; private long _count; public _(IObserver<double?> observer, IDisposable cancel) : base(observer, cancel) { _sum = 0; _count = 0; } public void OnNext(int? value) { checked { try { if (value.HasValue) { _sum += value.Value; _count++; } } catch (Exception error) { _observer.OnError(error); base.Dispose(); } } } public void OnError(Exception error) { _observer.OnError(error); base.Dispose(); } public void OnCompleted() { if (_count > 0) _observer.OnNext((double)_sum / (double)_count); else _observer.OnNext(null); _observer.OnCompleted(); base.Dispose(); } } private readonly IObservable<int?> _source; public AverageInt32Nullable(IObservable<int?> source) { _source = source; } protected override _ CreateSink(IObserver<double?> observer, IDisposable cancel) { return new _(observer, cancel); } protected override IDisposable Run(_ sink) { return _source.SubscribeSafe(sink); } } }