valid_raw_connection

# File activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 1106
        def valid_raw_connection
          (@verified && @raw_connection) ||
            # `allow_retry: false`, to force verification: the block won't
            # raise, so a retry wouldn't help us get the valid connection we
            # need.
            with_raw_connection(allow_retry: false, materialize_transactions: false) { |conn| conn }
        end