def stop_gracefully(timeout)
      if @mode == :http
        @client.close
      else
        @client.unusable.each { |id| @client.close_one(id, propagate = false) }
      end
      finish_terminating(timeout)
    end
def stop_gracefully(timeout)
      if @mode == :http
        @client.close
      else
        @client.unusable.each { |id| @client.close_one(id, propagate = false) }
      end
      finish_terminating(timeout)
    end
Gracefully stop processing
 Close clients except for authorization

 === Parameters
 timeout(Integer):: Maximum number of seconds to wait after last request received before
   terminating regardless of whether there are still unfinished requests

 === Return
 true:: Always return true