@JsonPropertyDescription(DESCRIPTION_PREFIX + "the statistics produced by the Benchmark Cluster Test job.")
    @JsonProperty("benchmarkCluster")
    public List<DocRef> getBenchmarkClusterDocRefs() {
        return benchmarkClusterDocRefs;
    }
Create a list of {@link DocRef} objects that are associated with a single {@link InternalStatisticKey}
stroom-statistics/stroom-statistics-impl/src/main/java/stroom/statistics/impl/InternalStatisticsConfig.java