URI: how to distinguish from invalid port vs no port number

Hey,

I read that default port was rejected in https://github.com/hyperium/http/issues/11.

However, the current API has pub fn port(&self) -> Option<Port<&str>> but it's not possible to
distinguish when invalid port number vs when no port number.
.
Example:

let uri: Uri = "/hello/world".parse().unwrap();
assert!(uri.port().is_none());

let uri: Uri = "/hello/world:-9933".parse().unwrap();
assert!(uri.port().is_none());

Opinions about having pub fn port(&self) -> Result<Option<Port<&str>, Error> or something similar?

Start with the Uri::port entry point and the examples in this issue, then read hyperium/http#11 to understand the earlier decision about default ports. Determine how the API should distinguish an absent port from an invalid port, with both "/hello/world" and "/hello/world:-9933" covered as completion cases.