Gets the total_count using the current filter constraints.

def get_count(self):
        """
        Gets the total_count using the current filter constraints.
        """
        params = self.get_params()
        params["offset"] = self.low_mark
        params["limit"] = 1

        r = self.resource._meta.api.http_resource("GET", self.resource._meta.resource_name, params=params)
        data = self.resource._meta.api.resource_deserialize(r.text)

        number = data["meta"]["total_count"]

        # Apply offset and limit constraints manually, since using limit/offset
        # in the API doesn't change the total_count output.
        number = max(0, number - self.low_mark)
        if self.high_mark is not None:
            number = min(number, self.high_mark - self.low_mark)

        return number