docs: public void clear() {
  		streamNodes = new HashMap<>();
  		virtualSelectNodes = new HashMap<>();
  		virtualSideOutputNodes = new HashMap<>();
  		virtualPartitionNodes = new HashMap<>();
  		vertexIDtoBrokerID = new HashMap<>();
  		vertexIDtoLoopTimeout  = new HashMap<>();
  		iterationSourceSinkPairs = new HashSet<>();
  		sources = new HashSet<>();
  		sinks = new HashSet<>();
  	}