allout-write-contents-hook-handler is a compiled Lisp function in `
Implement `allout-encrypt-unencrypted-on-saves' for file writes
Return nil if all goes smoothly, or else return an informative
message if an error is encountered. The message will serve as a
non-nil return on `write-contents-functions' to prevent saving of
the buffer while it has decrypted content.
This behavior depends on Emacs versions that implement the