@Beta
    public OptionalDouble defaultPrecisionFactor() {
        return defaultPrecisionFactor != null ? OptionalDouble.of(defaultPrecisionFactor) : OptionalDouble.empty();
    }
Returns the list of {@link Continuation}s of this request. This is used by the executing grouping searcher to
allow pagination of grouping results.

@return the list of Continuations.
container-search/src/main/java/com/yahoo/search/grouping/GroupingRequest.java