*
   * <p>This method is similar to {@link java.util.concurrent.CompletableFuture#exceptionally}. It
   * can also serve some of the use cases of {@link java.util.concurrent.CompletableFuture#handle}
   * and {@link java.util.concurrent.CompletableFuture#handleAsync} when used along with {@link
   * #transform}.
   *
   * @param exceptionType the exception type that triggers use of {@code fallback}. The exception

    ```bash
    bazel test ${flags} //tensorflow/python/...
    ```

    For a single component e.g. softmax op:

    ```bash
    bazel test ${flags} tensorflow/python/kernel_tests/nn_ops:softmax_op_test
    ```

    For a single/parameterized test e.g. `test_capture_variables` in
    `tensorflow/python/saved_model/load_test.py`:

    (Requires `python>=3.7`)

## Configuration protocol

Ztunnel, of course, needs to be dynamically configured in order to make decisions on how it should handle traffic.
For this purpose, we chose to use xDS transport protocol due to our expertise and existing infrastructure, and because the protocol is well suited to our needs.

There may be many routes for a single address. For example, a webserver that is hosted in multiple datacenters may yield multiple IP addresses in its DNS response.

In limited situations OkHttp will retry a route if connecting fails:

	// map for bucket metrics and handle them specially.

	// Add the serverName and poolIndex labels to all non-cluster metrics.
	//
	// Also create metric group maps and set the cache.
	metricsCache := newMetricsCache()
	mgMap := make(map[collectorPath]*MetricsGroup)
	bucketMGMap := make(map[collectorPath]*MetricsGroup)
	for _, mg := range allMetricGroups {

// due to a missing new pool. This function tries to handle this
// scenario, albeit rare it seems to have occurred in the wild.
//
// since we do not explicitly disallow it, but it is okay for them
// expand and then we continue to rebalance.
func (z *erasureServerPools) updateRebalanceStats(ctx context.Context) error {
	var ok bool
	for i := range z.serverPools {
		if z.findIndex(i) == -1 {

// loadAuditMetrics - `MetricsLoaderFn` for audit
// such as failed messages and total messages.
func loadAuditMetrics(_ context.Context, m MetricValues, c *metricsCache) error {
	audit := logger.CurrentStats()
	for id, st := range audit {
		labels := []string{targetID, id}
		m.Set(auditFailedMessages, float64(st.FailedMessages), labels...)
		m.Set(auditTargetQueueLength, float64(st.QueueLength), labels...)

  echo "Copying $(pwd)/${ZTUNNEL_BIN_PATH} to ${TARGET_OUT_LINUX}/ztunnel"
  mkdir -p "${TARGET_OUT_LINUX}"
  cp "${ZTUNNEL_BIN_PATH}" "${TARGET_OUT_LINUX}/ztunnel"
  popd
}

# ztunnel binary vars (TODO handle debug builds, arm, darwin etc.)
ISTIO_ZTUNNEL_BASE_URL="${ISTIO_ZTUNNEL_BASE_URL:-https://storage.googleapis.com/istio-build/ztunnel}"

# If we are not using the default, assume its private and we need to authenticate

      code: Int,
      reason: String,
    )
  }

  /**
   * Process the next protocol frame.
   *
   *  * If it is a control frame this will result in a single call to [FrameCallback].
   *  * If it is a message frame this will result in a single call to [FrameCallback.onReadMessage].
   *    If the message spans multiple frames, each interleaved control frame will result in a
   *    corresponding call to [FrameCallback].

	<li>the index <code>x</code> is <i>in range</i> if <code>0 &lt;= x &lt; len(a)</code>,
	    otherwise it is <i>out of range</i></li>
</ul>

<p>
For <code>a</code> of <a href="#Array_types">array type</a> <code>A</code>:
</p>
<ul>
	<li>a <a href="#Constants">constant</a> index must be in range</li>
	<li>if <code>x</code> is out of range at run time,