protected FastSet<OtherNode> predecessors = new FastSet<OtherNode>();
protected FastSet<OtherNode> successors = new FastSet<OtherNode>();
//private HashSet<OtherNode> predecessors = new HashSet<OtherNode>();
//private HashSet<OtherNode> successors = new HashSet<OtherNode>();
protected FastSet<OtherNode> predecessors = new FastSet<OtherNode>();
protected FastSet<OtherNode> successors = new FastSet<OtherNode>();
//private HashSet<OtherNode> predecessors = new HashSet<OtherNode>();
//private HashSet<OtherNode> successors = new HashSet<OtherNode>();