@Override
	public Vertex getKeyedObject(long key) {
		if (keyIndices.contains(key)) {
			try {
				return vertices[keyIndices.get(key)];
			}
			catch (Exception e) {
				return null;
			}
		}
		return null;
	}
Remove all of the vertices from this VertexSet without changing
the capacity. Much faster than removing each vertex individually.
The EdgeSet for this graph gets cleared first.
Ghidra/Framework/Generic/src/main/java/ghidra/util/graph/VertexSet.java