Let's say we want to migrateFoo fromPi0 toPi1, using Dispatcher.

The current protocol is then:

1. Dispatcher sends pubsub message toPi0 (migrate Foo)
2. Pi0 sends pubsub message toPi1 (run my snapshot of Foo)
3. Foo successfully migrated toPi1
4. Pi1 sends an ACK back toPi0
5. Pi0 sends ACK back to Dispatcher (your request was successful)

IfPi0 dies after step 3 but before step 5, Dispatcher will never receive an ACK, the migrate request will timeout and the user will think the migration failed even though it succeeded.
Maybe instead of listening for an ACK fromPi0, should Dispatcher listen for ACK fromPi1?