I have noticed that iMessages usually fail when outside a reliable data network area. Only after iOS attempts to deliver the message and fails does it offer to send it as a text message. Often the failure takes some time, and is not brought to my attention immediately. When circumstances are such that I reasonably suspect that iMessage will fail, I would like to skip the failure and send an SMS immediately.
How can I opt to send an SMS message instead of an iMessage without first attempting to send an iMessage?