public RingBufferPositionMarker(BaseLightStream untypedStream)
        {
            _ringBuffer      = null;
            _mbStreamWrapper = untypedStream as MultiBodyStreamWrapper;
            _start           = 0;
            var adapter = untypedStream as RingBufferStreamAdapter;

            if (adapter != null)
            {
                _ringBuffer = adapter._ringBuffer;
                _start      = _ringBuffer.GlobalReadPos;
            }
        }
 public RingBufferPositionMarker(RingBufferStreamAdapter ringBuffer)
 {
     _mbStreamWrapper = null;
     _ringBuffer      = ringBuffer._ringBuffer;
     _start           = _ringBuffer.GlobalReadPos;
 }