docs: @NonNull
      @Override
      public Flowable<Changes> observeChanges(@NonNull BackpressureStrategy backpressureStrategy) {
          final Flowable<Changes> rxBus = changesBus.asFlowable();
  
          if (rxBus == null) {
              throw new IllegalStateException("Observing changes in StorIOSQLite requires RxJava");
          }
  
          return rxBus;
      }