Payload for {:budget_exhausted, %__MODULE__{}} - ADR-0019's outcome when Statifier.Interpreter.macrostep/1's fold spends Statifier.MachineState.max_macrostep_rounds without reaching quiescence.

A core effect, not a trace effect: it is the outcome of the call rather than diagnostics about it, so it must be observable with trace: false. Statifier.Effect.Trace.MacrostepStable is not emitted alongside it - the configuration did not stabilize - which keeps the three macrostep outcomes (stable, done, budget-exhausted) mutually exclusive.

configuration is the full configuration (ADR-0005, ancestors included) as the last round left it; budget is the value that was spent, i.e. max_macrostep_rounds for that fold; pending_internal_events is Statifier.MachineState.internal_events/1's ordered view of the queue, which is where a livelock's repeatedly-raised events pile up. macrostep/microstep/round are the counters as they stand at exhaustion - and microstep may well be 0, because a fold can livelock without any microstep ever running. round is the rounds-spent count: always equal to budget on this path, since exhaustion is reached only after the fold has spent exactly that many rounds (ADR-0020) - which is why there is no separate rounds_spent field.

The machine_state returned alongside this effect is a complete, resumable position (ADR-0012): step it through Statifier.Interpreter.microstep/1 to watch the cycle round by round.