Send a message without notifying recipient

It's late at night and I want to send someone a message. I don't want their phone going off waking them up, and I don't want to have to remember the message until tomorrow morning, instead I want an alternative send option to send the message without the notification. 

Sure they have the option to silence their notifications for the night, but maybe they forgot to turn that on, or maybe we need them to hear notifications generally, but in this case my message can wait until tomorrow.