Which rail a message goes out on, for a line that carries more than one.
Deliberately not "sms": an iMessage line offers no forced-SMS send, so the word would promise behaviour the channel doesn't have.
"sms"
Which rail a message goes out on, for a line that carries more than one.
Deliberately not
"sms": an iMessage line offers no forced-SMS send, so the word would promise behaviour the channel doesn't have.