with_new_connections_blocked

# File activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb, line 677
      def with_new_connections_blocked
        previous_value = nil
        synchronize do
          previous_value, @new_cons_enabled = @new_cons_enabled, false
        end
        yield
      ensure
        synchronize { @new_cons_enabled = previous_value }
      end