The Vertex type exposes the following members.
The edge firing manager is responsible for determining which successor edges fire, following satisfaction of a vertex. If this is null, it is assumed that all edges are to fire. If it is non-null, then each successor edge is presented to the EdgeFiringManager on it's FireIfAppropriate(Edge e) API to determine if it should fire.
The edge receipt manager is notified of the satisfaction (firing) of pre-edges, and is responsible for determining when the vertex is to fire. If it is null, then it is assumed that only if all incoming edges have fired, is the vertex to fire.
This property represents the firing method will be called when it is time to fire the vertex. The developer may substitute a delegate that performs some activity prior to actually firing the vertex. This substituted delegate must, after doing whatever it does, call the DefaultVertexFiringMethod(graphContext)...
A synchronizer, ip present, defines a relationship among vertices wherein all vertices wait until they are all ready to fire, and then they fire in the specified order.