    # File lib/phusion_passenger/abstract_request_handler.rb, line 333
            def soft_shutdown
                    unless @soft_terminated
                            @soft_terminated = true
                            @select_timeout = @soft_termination_linger_time
                            @graceful_termination_pipe[1].close rescue nil
                            if @detach_key && @pool_account_username && @pool_account_password
                                    client = MessageClient.new(@pool_account_username, @pool_account_password)
                                    begin
                                            client.detach(@detach_key)
                                    ensure
                                            client.close
                                    end
                            end
                    end
            end