Just one more thought: another problem we're going to have is that you can have views loaded in one client but not another, so while appends are added whenever the view is loaded that isn't true for the rest of the API.

For example, if you start Patchbay and do a flumedb.append() followed by flumedb.rebuild() then all of the active views will append and then self-destruct. If you switch to Patchwork and it has different views, then they'll see the append but not the rebuild, because from the perspective of flumedb that rebuild has already been completed.

I suppose my concerns are that:

1. We're attempting full rebuilds on level views that support del() natively.
2. Some/many views don't support rebuilds in the first place.
3. Rebuilds are not respected by inactive views.