with_subscriptions_connection

# File actioncable/lib/action_cable/subscription_adapter/postgresql.rb, line 36
      def with_subscriptions_connection(&block) # :nodoc:
        ar_conn = ActiveRecord::Base.connection_pool.checkout.tap do |conn|
          # Action Cable is taking ownership over this database connection, and
          # will perform the necessary cleanup tasks
          ActiveRecord::Base.connection_pool.remove(conn)
        end
        pg_conn = ar_conn.raw_connection

        verify!(pg_conn)
        pg_conn.exec("SET application_name = #{pg_conn.escape_identifier(identifier)}")
        yield pg_conn
      ensure
        ar_conn.disconnect!
      end