Int 61 Fn 1A  - PC/tcp Kernel V2.05+ - "net_write" - Write To The Network  [N]

   AH = 1Ah
   BX = network descriptor
   CX = number of bytes to transmit (0000h allowed)
   DX = send options (see below)
   DS:SI -> data to be written

Return: CF clear if successful
       AX = number of bytes actually written
       DX = ???
   CF set on error
       AX = error code (see INT 61"PC/TCP")

Notes: the installation check consists of testing for the signature "TCPTSR"
     three bytes beyond the start of the interrupt handler
   INT 61 is the default; PC/TCP v2.05 may be configured to use any
     interrupt from 20h through E0h

See Also: INT 61"PC/TCP",INT 61/AH=00h"PC/TCP",INT 61/AH=1Bh,INT 61/AH=1Ch

See Also: INT 63/AH=19h"BW-TCP",INT 63/AH=1Bh"BW-TCP"

Bitfields for send options:
 bit 0 signal "URG"ent data
 bit 3 attempt rerouting on non-stream calls if first attempt fails
 bit 4 send data with PUSH flag (no override of Nagle)
   (see option 0Ch)
 bit 5 fail rather than truncating datagram
 bit 6 fail rather than blocking
 bit 7 broadcast packet