9947bf9351
Timer is a complex struct, allow adding it to a struct that uses #[derive(ToMigrationState)]; similar to vmstate_timer, only the expiration time has to be preserved. In fact, because it is thread-safe, ToMigrationStateShared can also be implemented without needing a cell or mutex that wraps the timer. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>