Compute a RoutingResult for a path described as an array of stops. This will call ServerRouting::computePath() repeatedly for each (source node, target node) pairs of the path, and merge the resulting RoutingResults togeter.
Plugins may override this method to do special treatment the very first time a routing computation is done. This will only called the first time the graph is drawn.
When computing a path made of several stops, one graph is generated for each (startNode, endNode) pairs of the path. This method should merge two graphs into another one.
Plugins should override this method to serialize the graph model object into a string, sent back to the client. The default implementation returns the object directly.