def total(self):
        """
        Return the total (virtual) size of the process in bytes. If process
        information is not available, get the best number available, even if it
        is a poor approximation of reality.
        """
        if self.system_total.available:
            return self.system_total.vsz
        elif self.asizeof_total: # pragma: no cover
            return self.asizeof_total
        else: # pragma: no cover
            return self.tracked_total