This don't make nooo sense. In theory, it should be almost semantically equivalent, `Futurable1` making only one more access to `Celluloid::Actor[:Futurable1]`. The `||=` is essentially checking for `nil` before assigning. Why it's such a big difference, I'd love to know.

futurable1.rb

require "benchmark"
require "celluloid"

class Futureable1
  include Celluloid
  
  class << self
    def p
      if Celluloid::Actor[:Futureable1].nil?
        Celluloid::Actor[:Futureable1] = Futureable1.pool(size: 2)
      end
      Celluloid::Actor[:Futureable1]
    end
  end

  def get
    sleep 0.5
  end
end

futurable2.rb

require "benchmark"
require "celluloid"
 
class Futureable2
  include Celluloid
  
  class << self
    def p
      Celluloid::Actor[:Futureable2] ||= Futureable2.pool(size: 2)
    end
  end
 
  def get
    sleep 0.5
  end
end

results.md

Benchmark.measure { 50.times { Futureable1.p.async.get } }.real
# => 12.045974
 
Benchmark.measure { 50.times { Futureable2.p.async.get } }.real
# => 0.002454