INT 62 - Cswitch - SEND MESSAGE                                                 
	AH = 0Bh
	CX = number of bytes to write
	DS:SI -> buffer
	DX = queue number (0-63)
Return: AX = result/message size
	    0000h no message was on queue
	    FFFEh triggered by something arriving, redo the call
	    FFFFh bad queue number
	    else  number of bytes in message
SeeAlso: AH=0Ah"Cswitch",AH=0Ch"Cswitch"