public boolean isInMemory() {
        return switch (this) {
            case ATTRIBUTE, DISTANCE, POSITIONS, GEOPOS, RANKFEATURES, SUMMARYFEATURES,
                    ATTRIBUTECOMBINER, ATTRIBUTE_TOKENS ->
                    true;
            default -> false;
        };
    }
Returns whether this transform always gets its value by accessing memory only
config-model/src/main/java/com/yahoo/vespa/documentmodel/SummaryTransform.java