reactiveui/ReactiveUI — pull request #211 by niik (2013-03-15 19:55:40+00:00)
Title: Prevent reset notification from firing twice

Reset is called from SuppressChangeNotifications so we don't need to explicitly do it from the derived collection.

```c#
public IDisposable SuppressChangeNotifications()
{
Interlocked.Increment(ref _suppressionRefCount);

if (!_hasWhinedAboutNoResetSub && _resetSubCount == 0) {
LogHost.Default.Warn("SuppressChangeNotifications was called (perhaps via AddRange), yet you do not");
LogHost.Default.Warn("have a subscription to ShouldReset. This probably isn't what you want, as ItemsAdded");
LogHost.Default.Warn("and friends will appear to 'miss' items");
_hasWhinedAboutNoResetSub = true;
}

return Disposable.Create(() => {
if (Interlocked.Decrement(ref _suppressionRefCount) == 0) {
Reset();
}
});
}
```

Includes a tiny test to verify.