}

    /**
     * Concatenates multiple byte arrays into a single array.
     */
    private static byte[] concat(byte[]... arrays) {
        int total = 0;
        for (byte[] a : arrays) {
            total += a.length;
        }
        byte[] res = new byte[total];
        int off = 0;
        for (byte[] a : arrays) {
            System.arraycopy(a, 0, res, off, a.length);
            off += a.length;
        }

## Una aplicación con callbacks

Veamos todo esto con un ejemplo.

Imagina que desarrollas una aplicación que permite crear facturas.

Estas facturas tendrán un `id`, `title` (opcional), `customer`, y `total`.

El usuario de tu API (un desarrollador externo) creará una factura en tu API con un request POST.

Luego tu API (imaginemos):

* Enviará la factura a algún cliente del desarrollador externo.
* Recogerá el dinero.

  )

  constructor() : this(5, 5, TimeUnit.MINUTES)

  /** Returns the number of idle connections in the pool. */
  fun idleConnectionCount(): Int = delegate.idleConnectionCount()

  /** Returns total number of connections in the pool. */
  fun connectionCount(): Int = delegate.connectionCount()

  internal val connectionListener: ConnectionListener
    get() = delegate.connectionListener

  /** True if this web socket failed and the listener has been notified. */
  private var failed = false

  /** Total number of pings sent by this web socket. */
  private var sentPingCount = 0

  /** Total number of pings received by this web socket. */
  private var receivedPingCount = 0

  /** Total number of pongs received by this web socket. */
  private var receivedPongCount = 0

		b.uint32(0)                      // number of the disk with the start of the central directory
		b.uint64(records)                // total number of entries in the central directory on this disk
		b.uint64(records)                // total number of entries in the central directory
		b.uint64(size)                   // size of the central directory

	Available  uint64 // in bytes
	MaxUsedPct int    // Used disk percentage of most filled disk, rounded down.
}

// TotalAvailable - total available space
func (p serverPoolsAvailableSpace) TotalAvailable() uint64 {
	total := uint64(0)
	for _, z := range p {
		total += z.Available
	}
	return total
}

// FilterMaxUsed will filter out any pools that has used percent bigger than max,

        SuggestUtil.deleteByQuery(ComponentUtil.getSearchEngineClient(), suggester.settings(), suggester.getIndex(), boolQueryBuilder);
    }

    /**
     * Gets the total number of words in the suggest index.
     *
     * @return The total number of words.
     */
    public long getAllWordsNum() {
        return suggester.getAllWordsNum();
    }

    /**

	ilmTransitionMissedImmediateTasksMD = NewCounterMD(transitionMissedImmediateTasks, "Number of missed immediate ILM transition tasks")
	ilmVersionsScannedMD                = NewCounterMD(versionsScanned, "Total number of object versions checked for ILM actions since server start")
)

// loadILMMetrics - `MetricsLoaderFn` for ILM metrics.
func loadILMMetrics(_ context.Context, m MetricValues, _ *metricsCache) error {

    // GET /api/admin/log/files
    @Execute
    public JsonResponse<ApiResult> files() {
        final List<Map<String, Object>> list = getLogFileItems();
        return asJson(new ApiResult.ApiLogFilesResponse().files(list).total(list.size()).status(ApiResult.Status.OK).result());
    }

    /**
     * Downloads a specific log file by ID.
     *
     * @param id the base64-encoded filename of the log file to download

    }

    int readFsFullSizeInformationWireFormat(final byte[] buffer, int bufferIndex) {
        final int start = bufferIndex;

        final SmbInfoAllocation info = new SmbInfoAllocation();

        // Read total allocation units.
        info.alloc = readInt8(buffer, bufferIndex);
        bufferIndex += 8;

        // read caller available allocation units
        info.free = readInt8(buffer, bufferIndex);