OUT PUCHAR Buf,                 	// destination,
  IN  PNDIS_PACKET Packet,         	// source packet,
  IN  UINT Offset,                 	// offset in packet,
  IN  UINT Length                  	// number of bytes to copy

Routine Description:

    Copies bytes from a packet into a buffer. Used to copy data
    out of a packet during loopback indications.


    Buf - the destination buffer
    Packet - the source packet
    Offset - the offset in the packet to start copying at
    Length - the number of bytes to copy

Return Value:

    The actual number of bytes copied; will be less than Length if
    the packet length is less than Offset+Length.