Expand description
Result err variant methods, e.g map_err_or()
§Examples
use result_either::ResultExt;
let ok: Result<i32, &str> = Ok(1);
let err: Result<i32, &str> = Err("err");
assert_eq!(ok.map_err_or(0, str::len), 0);
assert_eq!(err.map_err_or(0, str::len), 3);