private static String reasonDescription(int reason) {
        switch (reason) {

            case CANNOT_FIND_CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR:
                return "Cannot find client characteristic config descriptor";
            case CANNOT_WRITE_CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR:
                return "Cannot write client characteristic config descriptor";
            case CANNOT_SET_LOCAL_NOTIFICATION:
                return "Cannot set local notification";
            case UNKNOWN:
            default:
                return "Unknown error";
        }
    }
Should return one of {@link #CANNOT_SET_LOCAL_NOTIFICATION}, {@link #CANNOT_FIND_CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR},
{@link #CANNOT_WRITE_CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR}

@return the reason
rxandroidble/src/main/java/com/polidea/rxandroidble2/exceptions/BleCannotSetCharacteristicNotificationException.java