Function expand

pub fn expand<T, const N: usize>(
    expander: &dyn HkdfExpander,
    info: &[&[u8]],
) -> T
where
    T: From<[u8; N]>,

HKDF-Expand(PRK, info, L) to construct any type from a byte array.

• PRK is the implicit key material represented by this instance.
• L := N; N is the size of the byte array.
• info is a slice of byte slices, which should be processed sequentially (or concatenated if that is not possible).

This is infallible, because the set of types (and therefore their length) is known at compile time.