This would be a simple API enhancement and would allow easier building of URLs, like

>>> SplitResult("rtp", address, query=urlencode(query)).geturl()
"rtp://localhost:5004?rtcpport=5005"

It seems the best way to do this at the moment is annoyingly verbose:

SplitResult("rtp", address, path="", query=urlencode(query), fragment="").geturl()

The way hinted by the documentation can leave an ugly empty query string:

>>> query = ()
>>> "rtp://%s?%s" % (address, urlencode(query))
"rtp://localhost:5004?"

This enhancement would also allow easy parsing of usernames, ports, etc:

>>> SplitResult(netloc="[::1]:0").hostname
"::1"
>>> SplitResult(netloc="[::1]:0").port
0

Looking at the code, I think this could be implemented by adding an explicit constructor to each of the concrete classes, with arguments defaulting to "" or b"" as appropriate.