namespace System.Reactive.Linq.ObservableImpl { internal sealed class AverageInt64Nullable : Producer<double?, AverageInt64Nullable._> { internal sealed class _ : Sink<long?, double?> { private long _sum; private long _count; public _(IObserver<double?> observer) : base(observer) { _sum = 0; _count = 0; } public override void OnNext(long? value) { checked { try { if (value.HasValue) { _sum += value.Value; _count++; } } catch (Exception error) { ForwardOnError(error); } } } public override void OnCompleted() { if (_count > 0) ForwardOnNext((double)_sum / (double)_count); else ForwardOnNext(null); ForwardOnCompleted(); } } private readonly IObservable<long?> _source; public AverageInt64Nullable(IObservable<long?> source) { _source = source; } protected override _ CreateSink(IObserver<double?> observer) { return new _(observer); } protected override void Run(_ sink) { sink.Run(_source); } } }