WinsSendDatagram(
  IN  tDEVICECONTEXT  *pDeviceContext,
  IN  PIRP            pIrp,
  IN  BOOLEAN         MustSend
  );
Routine Description:

    This Routine handles sending a datagram down to the transport. MustSend
    it set true by the Send Completion routine when it attempts to send
    one of the queued datagrams, in case we still don't pass the memory
    allocated check and refuse to do the send - sends will just stop then without
    this boolean.

Arguments:

    pIrp - a  ptr to an IRP

Return Value:

    NTSTATUS - status of the request