Function replay 

pub fn replay<I>(
    events: I,
    config: &ReplayConfig,
) -> Result<ReplayResult, ReplayError>
where
    I: IntoIterator<Item = Result<EngineEvent, JournalError>>,

Replay events from an iterator through the reducer.

Implements JOURNAL_SPEC §9.2:

1. First event MUST be RunMeta with seq=1.
2. Schema version must be supported.
3. run_id must be consistent with RunMeta.
4. seq must be contiguous.
5. event_id must be unique.
6. Checkpoint run_id and state hash must match if checkpoint skip is used.
7. In strict mode, reducer errors halt replay.