pub trait ReadonlyIndex: Send + Sync {
// Required methods
fn as_any(&self) -> &dyn Any;
fn as_index(&self) -> &dyn Index;
fn change_id_index(
&self,
heads: &mut dyn Iterator<Item = &CommitId>,
) -> Box<dyn ChangeIdIndex>;
fn start_modification(&self) -> Box<dyn MutableIndex>;
}