public RemoverManager track(Remover remover){
  if (handlers == null) {
    handlers=new ArrayList<>();
  }
  handlers.add(remover);
  return this;
}

public RemoverManager track ( Remover remover ) { if ( handlers == null ) { handlers = new ArrayList < > ( ) ; } handlers . add ( remover ) ; return this ; }
tracks a new handler so that it can be removed in bulk .
