Creates a new I/O error from a known kind of error and a string literal.

Contrary to Error::new, this macro does not allocate and can be used in const contexts.

Example

#![feature(io_const_error)]
use std::io::{const_error, Error, ErrorKind};

const FAIL: Error = const_error!(ErrorKind::Unsupported, "tried something that never works");

fn not_here() -> Result<(), Error> {
    Err(FAIL)
}