SubgraphEvent

event happened inside the subgraph that node runs in step. A subgraph sends every event that a stream of its own would have, from the NodeStarted of its first node to its Completed or Interrupted, and they arrive after the NodeStarted of node and before its NodeCompleted. The steps inside event are those of the subgraph, which start at 1 on every visit.

graph.stream(case, config).collect { event ->
    if (event is GraphEvent.SubgraphEvent) {
        val inside = event.event
        if (inside is GraphEvent.NodeStarted) println("${event.node} > ${inside.node} started")
    }
}

When the subgraph has a subgraph of its own, event is a SubgraphEvent again. innermost and path read through the layers.