ProcessLeases.java

        Observable<Lease> leases = queryLeases(timeSlice)
                .flatMap(Observable::from)
                .map(row -> new Lease(timeSlice.getTime(), row.getInt(1), row.getString(2), row.getBool(3)))
                .filter(lease -> !lease.isFinished())
                .toList()
                .repeat()
                .takeUntil(List::isEmpty)
                .flatMap(Observable::from);
                // At this point I want to fetch the tasks for the lease,
                // execute each task, then delete the tasks partition,
                // and reschedule the tasks for subsequent execution
        leases.subscribe(
                System.out::println,
                Throwable::printStackTrace,
                () -> System.out.println("done!")
        );