I don't see an option to send text (browsed through README and Issues), is this not possible with croc? With Magic Wormhole it's the default to get a message prompt when running "wormhole send". Or you can do it as a oneliner with "wormhole send --text 'something'". Wormhole William can do this as well IIRC.

I use MWH often for sending stuff like URL's, passwords, API keys... having to create a file for that is quite annoying (and remembering to delete it afterwards).

"brew install magic-wormhole" or "sudo apt-get install magic-wormhole" is easy enough and I don't hang around with people who use Windows. ;)

Resumable file transfers sound like a great feature though. Not sure it's implementable with MWH the way it now works.