instance method with_role_and_shard

# File activerecord/lib/active_record/connection_handling.rb, line 374
      def with_role_and_shard(role, shard, prevent_writes)
        prevent_writes = true if role == ActiveRecord.reading_role

        append_to_connected_to_stack(role: role, shard: shard, prevent_writes: prevent_writes, klasses: [self])
        begin
          return_value = yield
          return_value.load if return_value.is_a? ActiveRecord::Relation
          return_value
        ensure
          self.connected_to_stack.pop
        end
      end