@abc.abstractmethod<EOL><INDENT>def next_chunk_boundaries(self, buf, prepend_bytes=<NUM_LIT:0>):<DEDENT>
Computes the next chunk boundaries within `buf`.

        Note:
            If called more than once, output depends on `all` previous calls of this function: The chunking algorithm is
            applied to the concatenation of all `buf` values.

        Args:
            buf (bytes): The message that is to be chunked.
            prepend_bytes (Optional[int]): Optional number of zero bytes that should be input to the chunking algorithm
                before `buf`.

        Returns:
            iterable: An iterable yielding chunk boundary positions relative to `buf`.