# File lib/vcr/structs.rb, line 61
      def initialize(*args)
        super

        if body && !body.is_a?(String)
          raise ArgumentError, "#{self.class} initialized with an invalid body: #{body.inspect}."
        end

        # Ensure that the body is a raw string, in case the string instance
        # has been subclassed or extended with additional instance variables
        # or attributes, so that it is serialized to YAML as a raw string.
        # This is needed for rest-client.  See this ticket for more info:
        # http://github.com/myronmarston/vcr/issues/4
        self.body = String.new(body.to_s)
      end