Function faulted 

pub fn faulted(why: JsValue) -> Error

A rejection as an std::io::Error.

The exception’s own name is what decides the kind, so “nothing is there” and “this is not ours to write” reach the container in the spelling it already acts on — a read of an entry that was never written answers None in an origin exactly as it does in a directory.

By value because that is the shape map_err asks for, which is the only way this is ever called.