t the URL class performs port normalization as per the WHATWG spec.
Default ports for "http", "https", "ws", "wss", and "ftp" schemes are always
treated as `None`.

For example:

assert httpx.URL("http://www.example.com") == httpx.URL("http://www.example.com:80")
assert httpx.URL("http://www.example.com:80").port is None
)