public void initialize(List<FlattenedItem> list, int startPosition) {
        this.startPosition = startPosition;
        items = list;
        reinitialize();
    }
A label we should use to match candidate terms for.
Used to propagate a label from e.g. reference conditions to named conditions
container-search/src/main/java/com/yahoo/prelude/semantics/engine/RuleEvaluation.java