Allow asking not just for the latest patch, but also for a cumulative patch

[mitar]

So I think maybe doing a GET request with Version header + Parents header would give you a patch which is a cumulative patch which gets you from state at version at Parents to state at version at Version, without intermediate patches.

So this would not be as useful for resolving conflicts, but in a client-server scenario where there are no offline changes pending on the client, it would allow quick update after reconnecting to the latest version of state. And if at a later stage happens that you do have to resolve conflicts, you then go and fetch individual patches.

And for fetching a bunch of individual patches I would live this out of scope of this spec because things like HTTP2 and pipelining in general can make this not too painful.

[toomim]

This is allowed in the spec, since it only specifies that a server needs to catch the client up-to-date, but does not specify that it must give it all intermediate patches. The server is allowed to short-cut the intermediate patches, with a single aggregate patch.

We do not currently have a standard way to tell the server what style of patch-aggregation a client wants. But none of our implementations are at a point where they need this capability, yet. So I'm closing this issue until we have the need to standardize this behavior.