A helper class to assist in reading and writing persisted klips
Writes or returns klip depending on the working mode.
Reads a klip from a klip file specified by path under given key. If such klip is not found, a value provided by source is persisted and returned instead.
Converts a key and a klip provided by source to a writable form that's safe to append to klip file.
Writes and returns a klip provided by source to a klip file specified by path under given key.