Custom baud rates not working correctly on MacOS 15

[neilmendoza]

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.