pub trait TreeApi<M, SN, SL, IN, IL> {
fn node_unchanged(&self, new: &IN, old: &SN) -> bool;
fn node_recyclable(&self, new: &IN, old: &SN) -> bool;
fn node_update(&self, update: Update<&mut SN, IN>);
fn node_crate(&self, new: IN) -> SN;
fn leaf_unchanged(&self, new: &IL, old: &SL) -> bool;
fn leaf_recyclable(&self, new: &IL, old: &SL) -> bool;
fn leaf_update(&self, update: Update<&mut SL, IL>);
fn leaf_crate(&self, new: IL) -> SL;
fn get_meta(&self, value: Either<&SN, &SL>) -> M;
fn insert(&self, op: InsertOp<M>);
fn remove(&self, x: M);
}