Function any_contains_ignore_ascii_case 

pub fn any_contains_ignore_ascii_case<T, I>(s: T, sub_iter: I) -> Option<usize>
where
    T: AsRef<[u8]>,
    I: IntoIterator,
    <I as IntoIterator>::Item: AsRef<[u8]>,

Finds the first match of any substring from sub_iter within s, using ASCII case insensitive comparison.

The returned index is a byte offset into s. Iteration order decides which candidate is considered first.