Saving iMessage draft for New Conversation

IOS is on it's 11th iteration and soon 12th will be coming out in September and there is no good text message draft saving feature.. Android has this simple text message draft saving function for a long, long time. Here is bummer. In IOS, when I select/copy new phone number(not in my contact list) from email,SMS text message, some contents,etc and start new text iMessage/SMS conversation; soon as I leave this new conversation, my text contents in iMessage is gone, gone. I like to go back and forth to add contents and often leave to finish the text message(like return to message list to open another text message to copy portion of it's contents or go to Home screen to launch another App to pick up contents, whatever) before sending this new message. In Android, for example I start text message, in middle, I go to the message list to open other message for copy some portion of contents while draft is saved with "To" phone number/s and my unfinished text and list that new conversation draft on top of the list as the recent message. I can open it and update and leave to come back or send. Not like IOS, where I have to open some text app like Notes, write text than copy/paste in new message to send. Come on Apple. please add draft savings feature to iMessage. not a rocket science.