C# telnet client and server with RFC2217 option. (only server support for now.)
Use SerialPortStream from https://github.com/Ellerbach/serialapp for Linux Serial port.
Use System.IO.Ports.SerialPort for Windows.
This project used VSCode.
It's normal that you get this error.
The nuget package do not carry the necessary Linux serial library. You'll basically will need to compile them. It is documented on the GitHub page. In short:
git clone https://github.com/jcurl/serialportstream.git
cd serialportstream/
cd dll/serialunix/
./build.shBuild using 'Production' configuration for Linux build.
dotnet publish --configuration Production