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When you check the benchmarks, it is common to see several tools of different types compared as equivalent.

Specifically, to see Uvicorn, Starlette and FastAPI compared together (among many other tools).

The simpler the problem solved by the tool, the better performance it will get. And most of the benchmarks don't test the additional features provided by the tool.

The hierarchy is like:

* **Uvicorn**: an ASGI server

   * problematic AtomicReferenceFieldUpdaterAtomicHelper code path. However, the same problem *does*
   * matter with AggregateFutureState, which does not have an Unsafe-based helper.
   *
   * This same problem is one of the reasons for us to likewise use package-private for the fields
   * in Waiter.
   */

  /**

## Accessing the request body in an exception handler { #accessing-the-request-body-in-an-exception-handler }

/// tip

To solve this same problem, it's probably a lot easier to use the `body` in a custom handler for `RequestValidationError` ([Handling Errors](../tutorial/handling-errors.md#use-the-requestvalidationerror-body){.internal-link target=_blank}).

Nevertheless, if you just use `pip` directly, the packages would be installed in your **global Python environment** (the global installation of Python).

### The Problem { #the-problem }

So, what's the problem with installing packages in the global Python environment?

   * call cancel() and be unable to cancel the delegate.
   * There are a number of ways to solve this, none of which are very pretty, and it is currently
   * believed to be a purely theoretical problem (since the other actions should supply sufficient
   * write-barriers).
   */

  @LazyInit private @Nullable ListenableFuture<V> delegateRef;
  @LazyInit private @Nullable ScheduledFuture<?> timer;

   * problematic AtomicReferenceFieldUpdaterAtomicHelper code path. However, the same problem *does*
   * matter with AggregateFutureState, which does not have an Unsafe-based helper.
   *
   * This same problem is one of the reasons for us to likewise use package-private for the fields
   * in Waiter.
   */

  /**

/**
 * Tests for {@link FreshValueGenerator}.
 *
 * @author Ben Yu
 */
@NullUnmarked
public class FreshValueGeneratorTest extends TestCase {

  @AndroidIncompatible // problem with equality of Type objects?
  public void testFreshInstance() {
    assertFreshInstances(
        String.class,
        CharSequence.class,
        Appendable.class,
        StringBuffer.class,

/// tip | Tipp

Auch die Integration anderer Authentifizierungs-/Autorisierungsanbieter wie Google, Facebook, X (Twitter), GitHub, usw. ist möglich und relativ einfach.

Das komplexeste Problem besteht darin, einen Authentifizierungs-/Autorisierungsanbieter wie solche aufzubauen, aber **FastAPI** reicht Ihnen die Tools, das einfach zu erledigen, während Ihnen die schwere Arbeit abgenommen wird.

///

/// tip

Integrating other authentication/authorization providers like Google, Facebook, X (Twitter), GitHub, etc. is also possible and relatively easy.

The most complex problem is building an authentication/authorization provider like those, but **FastAPI** gives you the tools to do it easily, while doing the heavy lifting for you.

///

## **FastAPI** utilities { #fastapi-utilities }