In other words, we cannot use just `self._key_fn` because the order relationship is defined by `lt`, which is derived from `compare` - an external parameter to `TopCombineFn` and `Top` constructors. `self._key_fn` will return a key to use for comparisons, but the order will not always be captured but this key, since the constructors also accept an additional `compare` function.
[ Full content available at: https://github.com/apache/beam/pull/6570 ] This message was relayed via gitbox.apache.org for devnull@infra.apache.org
