Function find_case_insensitive_files 

pub fn find_case_insensitive_files(
    directory: &Path,
    expected_file_name: &str,
) -> Result<Vec<PathBuf>>

Every file in directory whose name matches expected_file_name ASCII case-insensitively.

Sorted on lowercase name then original bytes, so the order is the same twice.

A caller that has to produce an answer wants find_case_insensitive_file, which takes the first. A caller for which several matches is itself the finding wants this: on a case-sensitive filesystem two entries differing only by case are two real files, and which one the engine reads depends on the order a directory walk hands them back.

Errors

Propagates the io::Error from reading directory or one of its entries.