namespace System.Reactive.Linq.ObservableImpl { internal sealed class CombineLatestObserver<T> : SafeObserver<T> { private readonly object _gate; private readonly ICombineLatest _parent; private readonly int _index; private T _value; public T Value => _value; public CombineLatestObserver(object gate, ICombineLatest parent, int index) { _gate = gate; _parent = parent; _index = index; } public override void OnNext(T value) { lock (_gate) { _value = value; _parent.Next(_index); } } public override void OnError(Exception error) { Dispose(); lock (_gate) { _parent.Fail(error); } } public override void OnCompleted() { Dispose(); lock (_gate) { _parent.Done(_index); } } } }