I spent a couple of days trying to track down this bug as looked like it had been fixed...
#18
#212
However on MacOS 15, custom baud rates using this library don't seem to be working correctly again. I'm controlling a servo that needs a 1Mbps connection. I can use this library on Linux (running in a VM on the Mac) to communicate with it but the same code doesn't work directly on the Mac. I can control the servo using pyserial on MacOS though so it is possible.