Having a getShardIdAt method on the chunk (which is provided by the
ChunkManager) exposes the internal implementation of the ChunkManager. If you
get a ChunkManager with timestamp 100, you shouldn't be allowed to ask for where
that chunk was at timestamp 50, because this is a potential for programmer
error.

That's why I want the Chunk that you get from the CM to come with the same
Timestamp as the CM.

If doing Misha's suggestion unblocks integration with GPiTR I am fine with
checking it in, but we need to have a ticket to disallow that.