# Advanced User Guide

## Additional Features

The main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank} should be enough to give you a tour through all the main features of **FastAPI**.

In the next sections you will see other options, configurations, and additional features.

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

  * Explicitly opting into behavioral changes can be acceptable. For example, introducing Istio multi-cluster semantics.
* Ensure traffic between mesh workloads is securely encrypted with an Istio identity.
* Be lightweight enough to not limit adoption.
  * This puts a much tighter budget on CPU, memory, latency, and throughput requirements than traditional Istio sidecars.

Ztunnel was not designed to be a feature-rich data plane.

     * Exception.)
     */
    throw new UncheckedExecutionException(cause);
  }

  /*
   * Arguably we don't need a timed getUnchecked because any operation slow enough to require a
   * timeout is heavyweight enough to throw a checked exception and therefore be inappropriate to
   * use with getUnchecked. Further, it's not clear that converting the checked TimeoutException to

package lock

import (
	"strings"
	"testing"
)

func TestFixLongPath(t *testing.T) {
	// 248 is long enough to trigger the longer-than-248 checks in
	// fixLongPath, but short enough not to make a path component
	// longer than 255, which is illegal on Windows. (which
	// doesn't really matter anyway, since this is purely a string

   * test. This must return an Iterator that returns the expected elements passed to the constructor
   * in the given order. Warning: it is not enough to simply pull multiple iterators from the same
   * source Iterable, unless that Iterator is unmodifiable.
   */
  protected abstract I newTargetIterator();

  /**

  // +optional
  optional string selectedNode = 1;

  // PotentialNodes lists nodes where the Pod might be able to run.
  //
  // The size of this field is limited to 128. This is large enough for
  // many clusters. Larger clusters may need more attempts to find a node
  // that suits all pending resources. This may get increased in the
  // future, but not reduced.
  //
  // +listType=set
  // +optional

	SunOS)
		ARCH=$(isainfo -k)
		;;
	esac
}

## FIXME:
## In OSX, 'readlink -f' option does not exist, hence
## we have our own readlink -f behavior here.
## Once OSX has the option, below function is good enough.
##
## readlink() {
##     return /bin/readlink -f "$1"
## }
##
readlink() {
	TARGET_FILE=$1

	cd $(dirname $TARGET_FILE)
	TARGET_FILE=$(basename $TARGET_FILE)

      added += q.drainTo(buffer, numElements - added);
      if (added < numElements) { // not enough elements immediately available; will have to poll
        E e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);
        if (e == null) {
          break; // we already waited enough, and there are no more elements in sight
        }
        buffer.add(e);
        added++;
      }
    }

)

// errOutOfEntropy indicates that the a source of randomness (PRNG) wasn't able
// to produce enough random data. This is fatal error and should cause a panic.

      ATOMIC_HELPER.putNext(this, next);
    }

    void unpark() {
      // This is racy with removeWaiter. The consequence of the race is that we may spuriously call
      // unpark even though the thread has already removed itself from the list. But even if we did
      // use a CAS, that race would still exist (it would just be ever so slightly smaller).
      Thread w = thread;
      if (w != null) {