# File lib/puma/cluster.rb, line 56
    def spawn_workers
      diff = @options[:workers] - @workers.size

      upgrade = (@phased_state == :waiting)

      master = Process.pid

      diff.times do
        pid = fork { worker(upgrade, master) }
        @cli.debug "Spawned worker: #{pid}"
        @workers << Worker.new(pid, @phase)
      end

      if diff > 0
        @phased_state = :idle
      end
    end