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);
```