code: public void sendMessageToAllNeighbors(Message m) {
  		if (edgesUsed) {
  			throw new IllegalStateException("Can use either 'getOutgoingEdges()' or 'sendMessageToAllTargets()' exactly once.");
  		}
  		
  		edgesUsed = true;
  		
  		outValue.f1 = m;
  		
  		while (edges.hasNext()) {
  			Tuple next = (Tuple) edges.next();
  			VertexKey k = next.getField(1);
  			outValue.f0 = k;
  			out.collect(outValue);
  		}
  	}
docs: Sends the given message to all vertices that are targets of an outgoing edge of the changed vertex.
  This method is mutually exclusive to the method {@link #getOutgoingEdges()} and may be called only once.
  
  @param m The message to send.