- Enables syncing Geth and Parity diffs with same transformer lookup
- Maybe worth always hashing the storage key so we don't need a hashed
and not-hashed version in the key lookups?
- If processing a new diff for a row that already exists in the DB,
ignore the error without logging or queueing
- If processing a queued diff for a row that already exists, remove
it from the queue
- Replaces directly reading from a CSV
- Simplifies testing
- Should hopefully make it easier to plug in other sources for storage
diffs (e.g. differently formatted CSVs, JSON RPC, etc)
libraries/shared; adjust omni test_helpers to drop and recreate
checked_headers table to avoid reaching 1600 column limit after repeated
tests (dropping columns doesn't actually remove them from contributing
to that limit)