How enumerable classes work in Ruby

enumerable.rb

class CustomEnumerable

  include Enumerable
  
  def initialize(items)
    @items = items
  end
  
  def each(&block)
    puts __callee__
    @items.each {|item| yield item }
  end
  
end

enum = CustomEnumerable.new([1, 2, 3, 4, 5, 6, 7, 8])
enum.map {|e|  e }
enum.to_a
enum.take(1)