SubgraphPosition
data class SubgraphPosition(val nextNodes: List<String>, val step: Int = 0, val interruptedBefore: Boolean = false, val subgraphs: Map<String, SubgraphPosition> = emptyMap())
Where a run stands inside a subgraph that was added with StateGraph.subgraph. It is a Checkpoint without a state: the state of a subgraph is kept in the state of the graph around it.