set_shard

# File activerecord/lib/active_record/middleware/shard_selector.rb, line 70
        def set_shard(shard, &block)
          klass = options[:class_name]&.constantize || ActiveRecord::Base

          klass.connected_to(shard: shard.to_sym) do
            klass.prohibit_shard_swapping(options.fetch(:lock, true), &block)
          end
        end