Example of adding a custom header to a message

[soywod]

I try to build a message with custom headers comming from user input as &str. The header method accepts sth implementing Header, but I don't see how to parse my str as a valid Header.
Thanks for the help!

[link2xt]

You can implement Header trait for your own header like it is done here: https://github.com/lettre/lettre/blob/master/src/message/header/textual.rs

[Hugo-Persson]

Is it possible to use the text_header macro in my code, how do I import it?