Top Level domain static hash map, tld list is obtained from of iana.org
```rust,no_run extern crate tld;
assert!(tld::exist("com")); assert!(tld::exist("io")); assert!(tld::exist("lt")); assert!(tld::exist("ru")); assert!(tld::exist("de"));
assert!(!tld::exist("")); assert!(!tld::exist("moc"));
assert!(tld::TLD.len() > 1400); ```