Function attach 

pub(crate) fn attach(json: &str) -> String

The files chosen on the page (sources, files or their addresses) made fit for one multimedia message to a conversation (attach::make; what an earlier attaching made goes first), off the window’s thread: {round (as asked: the page keeps its latest), media: [{source, kind, ct, path, url, size, said}], said: [why each other did not go], limit (its words), max (bytes)}. Nothing travels until Send.