Fix inefficiencies, causes write delays to drop

[silverv]

Did some experiments and measurements to conclude that these changes introduce less write delay. It is also likely that CPU load will be decreased with these changes.

[silverv]

On Windows it is important to note that a REALTIME priority level can be assigned to the process.

[silverv]

This is a continuation of #1490

[silverv]

I am doing this to improve the performance of SLCAN in Yakut (https://github.com/OpenCyphal/yakut) and Yukon (https://github.com/OpenCyphal/yukon).

[zariiii9003]

With your changes the timeout parameter will do nothing.
Also, your title mentions write delays, but you change the read function?