append(buf, "percent", () -> osProbe.getSystemCpuPercent());
        final OsStats osStats = osProbe.osStats();
        buf.append("},");
        append(buf, "load_averages", () -> osStats.getCpu().getLoadAverage());
        buf.append("},");
    }

    private void appendFesenStats(final StringBuilder buf) {
        String stats = null;
        try {

     */
    // GET /api/admin/stats
    @Execute
    public JsonResponse<ApiResult> index() {
        final HashMap<String, Object> stats = new HashMap<>();
        stats.put("jvm", getJvmObj());
        stats.put("os", getOsObj());
        stats.put("process", getProcessObj());
        stats.put("engine", getEngineObj());
        stats.put("fs", getFsObj());

   *
   * <ul>
   *   <li>Both {@code xStats} and {@code yStats} must have the same {@code count}.
   *   <li>If that {@code count} is 1, {@code sumOfProductsOfDeltas} must be exactly 0.0.
   *   <li>If that {@code count} is more than 1, {@code sumOfProductsOfDeltas} must be finite.
   * </ul>
   */
  PairedStats(Stats xStats, Stats yStats, double sumOfProductsOfDeltas) {
    this.xStats = xStats;
    this.yStats = yStats;

}

func newBucketReplicationStats() *BucketReplicationStats {
	return &BucketReplicationStats{
		Stats: make(map[string]*BucketReplicationStat),
	}
}

// Empty returns true if there are no target stats
func (brs *BucketReplicationStats) Empty() bool {
	return len(brs.Stats) == 0 && brs.ReplicaSize == 0
}

// Clone creates a new BucketReplicationStats copy

   * versions.
   */
  public static Stats fromByteArray(byte[] byteArray) {
    checkNotNull(byteArray);
    checkArgument(
        byteArray.length == BYTES,
        "Expected Stats.BYTES = %s remaining , got %s",
        BYTES,
        byteArray.length);
    return readFrom(ByteBuffer.wrap(byteArray).order(ByteOrder.LITTLE_ENDIAN));
  }

  /**

	if len(r.mostRecentStats.Stats) == 0 {
		r.mostRecentStats = BucketStatsMap{Stats: make(map[string]BucketStats, 1), Timestamp: UTCNow()}
	}
	if len(bs.ReplicationStats.Stats) > 0 {
		r.mostRecentStats.Stats[bucket] = bs
	}
	r.mostRecentStats.Timestamp = UTCNow()
	r.mostRecentStatsMu.Unlock()
	return bs
}

// get the most current of in-memory replication stats  and data usage info from crawler.

		return 0
	}

	stats.RLock()
	defer stats.RUnlock()

	val, ok := stats.apiStats[api]
	if ok {
		return val
	}

	return 0
}

// Load returns the recorded stats.
func (stats *HTTPAPIStats) Load(toLower bool) map[string]int {
	if stats == nil {
		return map[string]int{}
	}

	stats.RLock()
	defer stats.RUnlock()

    assertThat(EMPTY_PAIRED_STATS.toString())
        .isEqualTo("PairedStats{xStats=Stats{count=0}, yStats=Stats{count=0}}");
    assertThat(MANY_VALUES_PAIRED_STATS.toString())
        .isEqualTo(
            "PairedStats{xStats="
                + MANY_VALUES_PAIRED_STATS.xStats()
                + ", yStats="
                + MANY_VALUES_PAIRED_STATS.yStats()
                + ", populationCovariance="

    assertThat(EMPTY_PAIRED_STATS.toString())
        .isEqualTo("PairedStats{xStats=Stats{count=0}, yStats=Stats{count=0}}");
    assertThat(MANY_VALUES_PAIRED_STATS.toString())
        .isEqualTo(
            "PairedStats{xStats="
                + MANY_VALUES_PAIRED_STATS.xStats()
                + ", yStats="
                + MANY_VALUES_PAIRED_STATS.yStats()
                + ", populationCovariance="

              + (values.xStats().mean() - xStats.mean())
                  * (values.yStats().mean() - yStats.mean())
                  * values.count();
    }
    yStats.addAll(values.yStats());
  }

  /** Returns an immutable snapshot of the current statistics. */
  public PairedStats snapshot() {
    return new PairedStats(xStats.snapshot(), yStats.snapshot(), sumOfProductsOfDeltas);
  }