I was curious what Tony's graph would look like using a SimpleDelegator as he suggested.

    (using ruby 1.9.3p194)
    Calculating -------------------------------------
             without dci     68507 i/100ms
                with dci     24409 i/100ms
          with delegator     46945 i/100ms
    -------------------------------------------------
             without dci  2240202.4 (±3.2%) i/s -   11235148 in   5.020463s
                with dci   412445.3 (±3.7%) i/s -    2074765 in   5.037113s
          with delegator  1018928.4 (±1.6%) i/s -    5117005 in   5.023310s

RUBY:

    require 'rubygems'
    require 'benchmark/ips'
    require 'delegate'

    class ExampleClass
      def foo; 42; end
    end

    module ExampleMixin
      def foo; 43; end
    end

    class ExampleProvisioner < SimpleDelegator
      def foo; 44; end

    Benchmark.ips do |bm|
      bm.report("without dci") { ExampleClass.new.foo }
      bm.report("with dci") do
        obj = ExampleClass.new
        obj.extend(ExampleMixin)
        obj.foo
      end
      bm.report("with delegator") do
        ExampleProvisioner.new(ExampleClass.new).foo
      end
    end