pub fn canonicalize_email(address: &str) -> Result<String>Expand description
Canonicalizes an email address for storage and matching.
Both components are lowercased, and ß is expanded to ss, so
Strauß@Example.com and strauss@example.com share one key.
Returns an error when the address exceeds 500 bytes or its final @ does
not separate nonempty local and domain parts.