Everything a migration step needs to reshape cached data. The db handle is
the untyped connection from getMigrationDb() — its store names are plain
string and its records are unknown, so a step can read old-shaped or
renamed records without type assertions. Use logger for progress/diagnostics.
Everything a migration step needs to reshape cached data. The
dbhandle is the untyped connection fromgetMigrationDb()— its store names are plainstringand its records areunknown, so a step can read old-shaped or renamed records without type assertions. Useloggerfor progress/diagnostics.