The mega backend keeps the whole account as an in-memory tree which
go-mega reconciles asynchronously from the server's event stream. After
an upload, delete or move the optimistic local update could be undone
moments later when go-mega replayed the corresponding server event,
re-adding a node to its parent. In a long-running process such as mount
or serve this could briefly show a just-deleted file in a listing, or
make a moved file reappear shortly afterwards.
Wait for the server to confirm uploads, deletes and moves so the
in-memory tree is settled before returning, matching what Rmdir and
Purge already do. The move wait was also previously started after the
server-side move so only the rename was covered.
Add an internal test reproducing the lingering listing via a tight
put/remove/list loop.
6728aa033e