NTClearContextCancel(
  IN  NBT_WORK_ITEM_CONTEXT    *pContext
  );
Routine Description:

    This Routine sets the cancel routine for
    ((tDGRAM_SEND_TRACKING *)(pContext->pClientContext))->pClientIrp
    to NULL.

    NbtConfig.JointLock should be held when this routine is called.

Arguments:

    status - a completion status for the Irp

Return Value:

    NTSTATUS - status of the request