@gvanrossum -- This might cause an issue with the flow control of the transport. Since the buffer size is calculated with only the payload (and not the entire datagram).

The write buffer could in theory be flooded with zero-length datagrams, and the high watermark will never be crossed.

@gvanrossum -- This might cause an issue with the flow control of the transport. Since the buffer size is calculated with only the payload (and not the entire datagram).

The write buffer could in theory be flooded with zero-length datagrams, and the high watermark will never be crossed.

Oh, that's a very good point. I think we could add a constant value to the "buffer size" for each packet added -- the only use for the buffer size is to interact with flow control. In fact, after skimming the UDP Wikipedia page, I think we can add 8 for each packet, since that's the protocol's header size.

Sorry, I'd like one more doc change. The code and docs are actually fine, but I feel this deserves a What's New entry (Doc/whatsnew/3.13.rst). A bullet in the existing asyncio section under "Improved Modules" should suffice. I'd like it to mention both the ability to send 0-length packets and the change to buffer size (since it can affect details around flow control). Probably a good idea to mention the latter in the news file too.

No worries :) Let me know what you think of this wording I just added!

Sorry Guido, just pushed a documentation change to for the version change note in the Documentation

Edit: Also pushed a typo fix (repeated "will now") sorry!

Thanks again, @ordinary-jamie!