The behaviour of several incremental encoders is inconsistent between
2.x and py3k.

In 2.x:
>>> enc = codecs.getincrementalencoder('utf-16')()
>>> enc.getstate()
0
>>> enc.setstate(0)
>>> enc.encode(u'abc')
'\xff\xfea\x00b\x00c\x00'

In py3k:
>>> enc = codecs.getincrementalencoder('utf-16')()
>>> enc.getstate()
2
>>> enc.setstate(0)
>>> enc.encode('abc')
b'a\x00b\x00c\x00'