code: def current_pos(self):
          
          new_ptr = _decode(
              self._read_fixed_block(0x0020), self.lo_fix_format['current_pos'])
          if new_ptr == self._current_ptr:
              return self._current_ptr
          if self._current_ptr and new_ptr != self.inc_ptr(self._current_ptr):
              logger.error(
                  'unexpected ptr change %06x -> %06x', self._current_ptr, new_ptr)
          self._current_ptr = new_ptr
          return self._current_ptr
docs: Get circular buffer location where current data is being written.