prepend_before_invocation

# File actionwebservice/lib/action_web_service/invocation.rb, line 54
      def prepend_before_invocation(*interceptors, &block)
        conditions = extract_conditions!(interceptors)
        interceptors << block if block_given?
        add_interception_conditions(interceptors, conditions)
        prepend_interceptors_to_chain("before", interceptors)
      end