pub trait StringExt {
// Required method
fn expand_tabs(&self, tab_size: u16) -> Cow<'_, str>;
// Provided method
fn expand_tabs_default(&self) -> Cow<'_, str> { ... }
}pub trait StringExt {
// Required method
fn expand_tabs(&self, tab_size: u16) -> Cow<'_, str>;
// Provided method
fn expand_tabs_default(&self) -> Cow<'_, str> { ... }
}