anchor.diff:    /**
      * Convert the given [value] to an integer, or throw a [RequestFailure]
      * exception if the [value] could not be converted.
  -   * 
  +   *
      * The value is typically the result of invoking either [getParameter] or
      * [getRequiredParameter].
      */
  
positive.code:    * passed a non-boolean value.
     */
    Response.expectedBoolean(Request request, String value)
      : this(request.id, 'Expected a boolean value, but found "$value"');
  
    /**
     * Initialize a newly created instance to represent an error condition caused
  
negative.code:    * Return a request parsed from the given [data], or `null` if the [data] is
     * not a valid json representation of a request. The [data] is expected to
     * have the following format:
     *
     *   {
     *     'id': String,
     *     'method': methodName,
  