Function escape 

pub fn escape(text: &str) -> String

Encode the five characters that let a value stop being a value.

escape_into with a buffer of its own, for the callers that want a value rather than an append: a caller assembling an attribute out of several pieces, and everything outside this crate that took this function before the buffer-writing form existed. Emitting into a buffer you already hold is the cheaper path and the one this crate’s own emitters take.