@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        FetchVector that = (FetchVector) o;
        return Objects.equals(map, that.map);
    }
Returns a new FetchVector, identical to {@code this} except for its values in the override's dimensions.
flags/src/main/java/com/yahoo/vespa/flags/FetchVector.java