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