# File lib/action_dispatch/middleware/callbacks.rb, line 21
    def self.to_prepare(*args, &block)
      if args.first.is_a?(Symbol) && block_given?
        define_method "__#{args.first}""__#{args.first}", &block
        set_callback(:prepare, "__#{args.first}""__#{args.first}")
      else
        set_callback(:prepare, *args, &block)
      end
    end