- Delete header on conflict to prompt data refresh (cascade deletes all
data associated with that block)
- Derive header hash from rpc payload rather than computing it from data
(prevents hash mismatch between blockchain and cache)
- mark header as checked if no matching logs
- mark header as checked if all matching logs persisted successfully
- batch convert and insert matching logs to enable transactional persist
- enable skipping previously checked block headers when restarting a sync
