Problem: When loading a document whilst passing an `OpObserver` we call
the OpObserver for every change in the loaded document. This slows down
the loading process for two reasons: 1) we have to make a call to the
observer for every op 2) we cannot just stream the ops into the OpSet in
topological order but must instead buffer them to pass to the observer.
Solution: Construct the OpSet first, then only traverse the visible ops
in the OpSet, calling the observer. For documents with a deep history
this results in vastly fewer calls to the observer and also allows us to
construct the OpSet much more quickly. It is slightly different
semantically because the observer never gets notified of changes which
are not visible, but that shouldn't matter to most observers.
Before this change i64 decoding did not work for negative numbers (not a
real problem because it is only used for the timestamp of a change),
and both u64 and i64 would allow overlong LEB encodings.
This is primarily useful when debugging documents which have been
corrupted somehow so you would like to see the ops even if you can't
trust them. Note that this is _not_ currently useful for performance
reasons as the hash graph is still constructed, just not verified.
* Don't panic on invalid gzip stream
Before this change automerge-rs would panic if the gzip data in
a raw column was invalid; after this change the error is propagated
to the caller correctly.
After some discussion with PVH I realise that the repo structure in the
last reorg was very rust-centric. In an attempt to put each language on
a level footing move the rust code and project files into ./rust
