Return a new Retry object with incremented retry counters.

        :param response: A response object, or None, if the server did not
            return a response.
        :type response: :class:`~urllib3.response.HTTPResponse`
        :param Exception error: An error encountered during the request, or
            None if the response was received successfully.

        :return: A new ``Retry`` object.

def increment(self, method=None, url=None, response=None, error=None,
                  _pool=None, _stacktrace=None):
        """ Return a new Retry object with incremented retry counters.

        :param response: A response object, or None, if the server did not
            return a response.
        :type response: :class:`~urllib3.response.HTTPResponse`
        :param Exception error: An error encountered during the request, or
            None if the response was received successfully.

        :return: A new ``Retry`` object.
        """
        if self.total is False and error:
            # Disabled, indicate to re-raise the error.
            raise six.reraise(type(error), error, _stacktrace)

        total = self.total
        if total is not None:
            total -= 1

        connect = self.connect
        read = self.read
        redirect = self.redirect
        status_count = self.status
        cause = 'unknown'
        status = None
        redirect_location = None

        if error and self._is_connection_error(error):
            # Connect retry?
            if connect is False:
                raise six.reraise(type(error), error, _stacktrace)
            elif connect is not None:
                connect -= 1

        elif error and self._is_read_error(error):
            # Read retry?
            if read is False or not self._is_method_retryable(method):
                raise six.reraise(type(error), error, _stacktrace)
            elif read is not None:
                read -= 1

        elif response and response.get_redirect_location():
            # Redirect retry?
            if redirect is not None:
                redirect -= 1
            cause = 'too many redirects'
            redirect_location = response.get_redirect_location()
            status = response.status

        else:
            # Incrementing because of a server error like a 500 in
            # status_forcelist and a the given method is in the whitelist
            cause = ResponseError.GENERIC_ERROR
            if response and response.status:
                if status_count is not None:
                    status_count -= 1
                cause = ResponseError.SPECIFIC_ERROR.format(
                    status_code=response.status)
                status = response.status

        history = self.history + (RequestHistory(method, url, error, status, redirect_location),)

        new_retry = self.new(
            total=total,
            connect=connect, read=read, redirect=redirect, status=status_count,
            history=history)

        if new_retry.is_exhausted():
            raise MaxRetryError(_pool, url, error or ResponseError(cause))

        log.debug("Incremented Retry for (url='%s'): %r", url, new_retry)

        return new_retry