Do not worry about it being buggy, or even it being bad (design, or code). Let others do that work for you :-)
It took a few minutes since I had to add a license and README, plus I did a quick test of it locally to make sure it still worked, which helped me discover that SASL authentication needed to be implemented, so I added that.
I agree other people could be interested in contributing, I'm just not sure how much interest there actually is for a PgBouncer alternative.
Do you know of a package/application/library that can be used to validate just the FEBE protocal of Postgres, and possibly stress/performance test it, as well. Such a test-suite would be great to independently test the various implementations of Postgres wire-compatible projects and products, including your roundabout.
A pair of programs. One to emulate Postgres server, another to emulate a Postgres client. These two programs would assume they are just talking to each other, and know exactly what to expect from the other side.
Then we can inject a protocol implementer (the system under test, or SUT) between these two programs and see if the SUT can make both these programs believe that they are still talking just with each other. This way we can validate the level of protocol support by the SUT. And if we can run this whole setup, multiple clients, a server, and the SUT, under controlled conditions, we can also evaluate the performance of each such protocol implementation.
The Postgres client emulator would send a predefined set of commands, and would know exactly what the response should be. The Postgres server emulator would know exactly what commands to expect, and the hard-coded responses to send for each incoming command.
The client emulator's knowledge of the responses would make it easy to catch any errors/bugs introduced by the SUT.
The Postgres server emulator would _not_ implement any server-side logic (command parsing, planning, etc.), to ensure the peak performance for each command it processes.
I was thinking of implementing such a Postgres server emulator back in around 2014, but for a different reason. IIRC, I was thinking of calling it Black Hole Postgres, to test the performance of my TPC-C implementation, DBYardstick [1].