public int neighborsToExploreAtInsert() {
        return neighborsToExploreAtInsert.orElse(DEFAULT_NEIGHBORS_TO_EXPLORE_AT_INSERT);
    }
Creates a new instance where values from the given parameter instance are used where they are present,
otherwise we use values from this.
config-model/src/main/java/com/yahoo/schema/document/HnswIndexParams.java