- Focus on header mode
- Add context to errors, trace guard clauses, warn on non-returned
errors
- Give errors distinct names so compiler will recognize if unchecked
- Remove redundant type declarations/fix typos
- Previously, we required that the first missing header match the
configured starting block number. This helps guarantee that we have
the necessary data for method polling in memory, but prevents the
process from moving forward if restarted after the starting block
has already been checked.
