@Override
    public int hashCode() {
        return Objects.hash(on, off);
    }
Adds nodeFlag to the provided flags set after removing the other member of this {@link NodeFlagPair}

@param isOn  The flag to add based on its state
@param flags Set to add to
stroom-core-shared/src/main/java/stroom/explorer/shared/NodeFlagPair.java