# File lib/grape/middleware/error.rb, line 79
      def format_message(message, backtrace, original_exception = nil)
        format = env[Grape::Env::API_FORMAT] || options[:format]
        formatter = Grape::ErrorFormatter.formatter_for(format, options)
        throw :error,
              status: 406,
              message: "The requested format '#{format}' is not supported.",
              backtrace: backtrace,
              original_exception: original_exception unless formatter
        formatter.call(message, backtrace, options, env, original_exception)
      end