Waiting asyncronous works completion simpley

Syncronized.cs

static class Syncronized
{
    public static void Invoke(Action<ManualResetEvent> action)
    {
        if (action == null) throw new ArgumentException("action");

        using (var signal = new ManualResetEvent(false))
        {
            action(signal);
            signal.WaitOne();
        }
    }
}