public IDisposable Subscribe(IObserver <R> observer)
        {
            var srcs   = sources;
            var n      = srcs.Length;
            var parent = new CombineCoordinator(observer, mapper, delayErrors, n);

            parent.Subscribe(srcs);
            return(parent);
        }
        public void Subscribe(ISignalObserver <R> observer)
        {
            var srcs = sources;
            var n    = srcs.Length;

            var parent = new CombineCoordinator(observer, mapper, delayErrors, n);

            observer.OnSubscribe(parent);

            parent.Subscribe(srcs);
        }
 public InnerObserver(CombineCoordinator parent, int index)
 {
     this.parent = parent;
     this.index  = index;
 }