INT 63 - BW-TCP - TCPIP.SYS - WRITE TO THE NETWORK
        AH = 19h
        DS:DI -> ???
        ???
Return: BX = number of bytes NOT written
        ???
Note:   calls AH=17h with interrupts disabled and ??? set to 01h
SeeAlso: AH=1Ah,AH=1Bh,INT 61/AH=1Ah"PC/TCP"

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