ActiveSupport::Concern 在 initialize 方法之前会运行 included 方法，而在 initialize 方法之后会运行 ClassMethods 方法。

下面是一个示例代码：

require 'active_support/concern'

module MyConcern
  extend ActiveSupport::Concern

  included do
    puts "Running included method"
  end

  def initialize(*args)
    super
    puts "Running initialize method"
  end

  module ClassMethods
    def class_method
      puts "Running class method"
    end
  end
end

class MyClass
  include MyConcern

  def initialize(*args)
    puts "Running MyClass initialize method"
    super
  end
end

MyClass.class_method

当你运行以上代码时，输出将会是：

Running included method
Running class method
Running MyClass initialize method
Running initialize method

可以看到，included 方法在 initialize 方法之前运行，而 ClassMethods 方法在 initialize 方法之后运行。