public IObservable <Change <TObject, TKey> > Watch(TKey key)
{
return(Observable.Create <Change <TObject, TKey> >
(
observer =>
{
lock (_locker)
{
var initial = _readerWriter.Lookup(key);
if (initial.HasValue)
{
observer.OnNext(new Change <TObject, TKey>(ChangeReason.Add, key, initial.Value));
}
return _changes.FinallySafe(observer.OnCompleted).Subscribe(changes =>
{
var matches = changes.Where(update => update.Key.Equals(key));
foreach (var match in matches)
{
observer.OnNext(match);
}
});
}
}));
}
public Optional <TObject> Lookup(TKey key)
{
return(_readerWriter.Lookup(key));
}