I want use this lib for 485，but I don't konw how to control the state

[VarianSikovsky]

First thank for you make this Very good library
Now I need a lib for serial，but I’m using a custom-made linux pc，and this pc has different serial for 485 ，I need change gpio state that is used to switch between read and write，fortunately the gpio is also RTS pin，so that I just need change RTS state， and I can switch between read and write
The issue is I don't how to use the CppLinuxSerial to change RTS state,the examples don't have this dome
I really hope to get your reply