usecore::fmt::Debug;/// References among nodes.
pubtraitRefs: Clone + Debug {/// Creates an empty references.
fnempty()->Self;/// Returns true if the references collection is empty.
fnis_empty(&self)->bool;/// Clears the references.
fnclear(&mutself);/// Removes the reference at the given `ref_idx`.
fnremove_at(&mutself, ref_idx:usize);/// Removes the node reference from references pointing to the node at given `ptr` location.
////// Returns the position of the `ptr` among references if it exists; None otherwise.
fnremove(&mutself, ptr:usize)->Option<usize>;}