System.Threading.ManualResetEventSlim.UpdateStateWithOp C# (CSharp) Method

        long UpdateStateWithOp(bool set)
        {
            long oldValue, newValue;
            do {
                oldValue = state;
                newValue = (long)(((oldValue >> 1) + 1) << 1) | (set ? 1u : 0u);
            } while (Interlocked.CompareExchange (ref state, newValue, oldValue) != oldValue);
            return newValue;
        }