pub trait ContentLanguageOption<'a> {
// Required method
fn content_language(&self) -> Option<&'a str>;
// Provided method
fn add_header(&self, builder: Builder) -> Builder { ... }
}
pub trait ContentLanguageOption<'a> {
// Required method
fn content_language(&self) -> Option<&'a str>;
// Provided method
fn add_header(&self, builder: Builder) -> Builder { ... }
}