Use zlib's crc32 routine instead of binascii when available.  zlib's is faster when compiled properly optimized and about the same speed otherwise.
Use zlib's crc32 routine instead of binascii when available.  zlib's is faster
when compiled properly optimized and about the same speed otherwise.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator