A disk snapshot of a sandbox that is writing no longer fails

A mode: "disk" snapshot of a running sandbox used to fail with "could not confirm that its writes reached its disk" whenever a program in it was writing. Its pause now waits for the sandbox to write out what it still held in memory before the snapshot is taken. That takes milliseconds when the sandbox is quiet and can take a few seconds while it writes. Memory snapshots are as fast as before. See the API guide.