results.txt

Warming up --------------------------------------
         Forwardable   148.719k i/100ms
                Send   334.975k i/100ms
         Simple call   380.722k i/100ms
Calculating -------------------------------------
         Forwardable      1.999M (± 5.0%) i/s -     10.113M in   5.073999s
                Send      7.768M (± 5.4%) i/s -     38.857M in   5.018102s
         Simple call     10.120M (± 6.8%) i/s -     50.636M in   5.027285s

test.rb

require 'benchmark/ips'
require 'forwardable'

class TestForwardable
  extend Forwardable
  def_delegators :@array, :size

  def initialize
    @array = (1..100).to_a
  end
end

class TestMethod
  def initialize
    @array = (1..100).to_a
  end

  def size
    @array.size
  end
end

class TestSend
  def initialize
    @array = (1..100).to_a
  end

  def size
    @array.send(:size)
  end
end

forwardable = TestForwardable.new
sender = TestSend.new
method = TestMethod.new

Benchmark.ips do |x|
  x.report("Forwardable") { forwardable.size }
  x.report("Send") { sender.size }
  x.report("Simple call") { method.size }
end