def shutdown
      stop
      @listeners.each{|s|
        if @logger.debug?
          addr = s.addr
          @logger.debug("close TCPSocket(#{addr[2]}, #{addr[1]})")
        end
        begin
          s.shutdown
        rescue Errno::ENOTCONN
          # when `Errno::ENOTCONN: Socket is not connected' on some platforms,
          # call #close instead of #shutdown.
          # (ignore @config[:ShutdownSocketWithoutClose])
          s.close
        else
          unless @config[:ShutdownSocketWithoutClose]
            s.close
          end
        end
      }
      @listeners.clear
    end
def shutdown
      stop
      @listeners.each{|s|
        if @logger.debug?
          addr = s.addr
          @logger.debug("close TCPSocket(#{addr[2]}, #{addr[1]})")
        end
        begin
          s.shutdown
        rescue Errno::ENOTCONN
          # when `Errno::ENOTCONN: Socket is not connected' on some platforms,
          # call #close instead of #shutdown.
          # (ignore @config[:ShutdownSocketWithoutClose])
          s.close
        else
          unless @config[:ShutdownSocketWithoutClose]
            s.close
          end
        end
      }
      @listeners.clear
    end
Shuts down the server and all listening sockets.  New listeners must be
 provided to restart the server.