Cannot operate multiple serial ports at the same time, which is a flaw

[tenutos]

It's really a great library, let me make a small suggestion.

Some operations should be based on a customizable device that is already open

Of course it doesn't affect the use, but it would be better to optimize it.

[Sunbreak]

Thanks for the sugguestion. However we are a small team and short of resource to develop further feature. Forks and PRs are welcome :)