internal EventKey(WeakEventManager manager, object source)
{
_manager = manager;
_source = source;
_hashcode = unchecked(manager.GetHashCode() + RuntimeHelpers.GetHashCode(source));
}
internal EventKey(WeakEventManager manager, object source, bool useWeakRef)
{
_manager = manager;
_source = new WeakReference(source);
_hashcode = unchecked(manager.GetHashCode() + RuntimeHelpers.GetHashCode(source));
}