KPD: Check that we handle a long sequence of multibyte characters correctly.
KPD: Explicit tests for special character extraction.
KPD: Tests working with index-based approach, need to add buffering.
KPD: Use a buffer with new index-based approach. The one large file test is about twice as fast as it was with the previous approach. https://www.pivotaltracker.com/story/show/60476394