The JS lib generates strings as output from `.getHeads`, while the Java API wants `ChangeHash` objects. Perhaps add a string ctor to ChangeHash and/or string arity to `encodeChangesSince`.
The JS lib generates strings as output from
.getHeads, while the Java API wantsChangeHashobjects.Perhaps add a string ctor to ChangeHash and/or string arity to
encodeChangesSince.