@Override
    public Single<Integer> requestMtu(final int mtu) {
        return Single.fromCallable(new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
                currentMtu = mtu;
                return mtu;
            }
        });
    }
Value used to disable notifications or indicatinos
mockrxandroidble/src/main/java/com/polidea/rxandroidble2/mockrxandroidble/RxBleConnectionMock.java