def _read_augmentation_data(self, entry_structs):
        """ Read augmentation data.

        This assumes that the augmentation string starts with 'z', i.e. that
        augmentation data is prefixed by a length field, which is not returned.
        """
        if not self.for_eh_frame:
            return b''

        augmentation_data_length = struct_parse(
            Struct('Dummy_Augmentation_Data',
                   entry_structs.Dwarf_uleb128('length')),
            self.stream)['length']
        return self.stream.read(augmentation_data_length)
 Read augmentation data.

        This assumes that the augmentation string starts with 'z', i.e. that
        augmentation data is prefixed by a length field, which is not returned.
        
product/runtime/src/main/python/java/_vendor/elftools/dwarf/callframe.py