* Add support for cloud sync, specifically GCP
This adds generic support for sync to cloud services, with specific
spuport for GCP. Adding others -- so long as they support a
compare-and-set operation -- should be comparatively straightforward.
The cloud support includes cleanup of unnecessary data, and should keep
total space usage roughly proportional to the number of tasks.
Co-authored-by: ryneeverett <ryneeverett@gmail.com>
In #3118 @ryneeverett mentioned that "key" suggests that this is a
secret, when in truth it's just a user identifier. So "ID" is a better
word for it than "key".
This avoids a vulnerability in tokio (#3085). The major version updates
of both actix-web and actix-rt required some signficant changes. Chief
among those, it turns out we were relying on actix-rt to run the
HttpServer in a different thread from the rest of the test, so that we
could talk to it from sync code in the test thread. This no longer
works, so the sync code is now run in a dedicated thread with
`actix_rt::task::spawn_blocking`.
