Formula for computing the current backoff

        :rtype: float

def get_backoff_time(self):
        """ Formula for computing the current backoff

        :rtype: float
        """
        # We want to consider only the last consecutive errors sequence (Ignore redirects).
        consecutive_errors_len = len(list(takewhile(lambda x: x.redirect_location is None,
                                                    reversed(self.history))))
        if consecutive_errors_len <= 1:
            return 0

        backoff_value = self.backoff_factor * (2 ** (consecutive_errors_len - 1))
        return min(self.BACKOFF_MAX, backoff_value)