withCheckpoint
fun <State> List<Checkpoint<State>>.withCheckpoint(checkpoint: Checkpoint<State>, maxHistory: Int = Int.MAX_VALUE): List<Checkpoint<State>>
Returns this history of a thread after checkpoint is saved, for a Checkpointer that keeps a history: the checkpoints with an earlier step, then checkpoint, and of those the last maxHistory.
A checkpoint replaces the one with the same step, because both stand at the same place of the run: a run that pauses before its next nodes, or in one of them, saves that place again.