private void TestEm()
{
const int offset = 3000;
int hr;
long l, l2;
IAMClockAdjust ca = new SystemClock() as IAMClockAdjust;
IReferenceClock rc = ca as IReferenceClock;
hr = rc.GetTime(out l);
DsError.ThrowExceptionForHR(hr);
hr = ca.SetClockDelta(offset);
DsError.ThrowExceptionForHR(hr);
hr = rc.GetTime(out l2);
DsError.ThrowExceptionForHR(hr);
Debug.Assert(l2 - l >= offset, "SetClockDelta");
}