public
    @Override
    PropertyMap clone() {
        PropertyMap clone = (PropertyMap) super.clone();
        clone.properties = cloneMap(this.properties);
        return clone;
    }
Return true if this value should be set in this map, false if the set should be propagated instead
This default implementation always returns true.
container-core/src/main/java/com/yahoo/processing/request/properties/PropertyMap.java