Fix 04cc0f781c47ebfb9f9b188a8e8aa423f276c0b1
Fix 04cc0f781c47ebfb9f9b188a8e8aa423f276c0b1

mypy complains that the type annotation should be Type[PAUSED] and
Type[NEED_DATA]. Sadly, the sentinels are hard to type.

python-hyper/h11