# `Statifier.Effect.BudgetExhausted`
[🔗](https://github.com/riddler/statifier-ex/blob/v2.0.0/lib/statifier/effect/budget_exhausted.ex#L1)

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.

# `t`

```elixir
@type t() :: %Statifier.Effect.BudgetExhausted{
  budget: pos_integer() | :infinity,
  configuration: MapSet.t(non_neg_integer()),
  macrostep: non_neg_integer(),
  microstep: non_neg_integer(),
  pending_internal_events: [Statifier.Event.t()],
  round: non_neg_integer()
}
```

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*Consult [api-reference.md](api-reference.md) for complete listing*