INT 21 u - LAN Manager Enhanced DOS - LOCAL NetMessageBufferSend
        AX = 5F40h
        DS:DX -> NetMessageBufferSend parameter structure (see below)
Return: AX = error code

Format of NetMessageBufferSend parameter structure:
Offset  Size    Description
 00h    DWORD   -> recipient name (name for specific user, name* for domain
                        name wide, * for broadcast)
 04h    DWORD   -> buffer
 08h    WORD    length of buffer

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