@Override
    public String toString() {
        return "InternalStatisticsConfig{" +
                "enabledStoreTypes=" + enabledStoreTypes +
                ", benchmarkClusterDocRefs=" + benchmarkClusterDocRefs +
                ", cpuDocRefs=" + cpuDocRefs +
                ", eventsPerSecondDocRefs=" + eventsPerSecondDocRefs +
                ", heapHistogramBytesDocRefs=" + heapHistogramBytesDocRefs +
                ", heapHistogramInstancesDocRefs=" + heapHistogramInstancesDocRefs +
                ", memoryDocRefs=" + memoryDocRefs +
                ", metaDataStreamSizeDocRefs=" + metaDataStreamSizeDocRefs +
                ", metaDataStreamsReceivedDocRefs=" + metaDataStreamsReceivedDocRefs +
                ", refDataStoreSize=" + refDataStoreSize +
                ", pipelineStreamProcessorDocRefs=" + pipelineStreamProcessorDocRefs +
                ", searchResultsStoreSize=" + searchResultsStoreSize +
                ", searchResultsStoreCount=" + searchResultsStoreCount +
                ", streamTaskQueueSizeDocRefs=" + streamTaskQueueSizeDocRefs +
                ", volumesDocRefs=" + volumesDocRefs +
                '}';
    }
Get the list of DocRefs that correspond to a particular key, where the type of the {@link DocRef}
is in the list of enabledStoreTypes.
stroom-statistics/stroom-statistics-impl/src/main/java/stroom/statistics/impl/InternalStatisticsConfig.java