return pool.Index
                }
        }
        // Should not happen, but print values just in case.
        panic(fmt.Errorf("reached end of serverPools (total: %v, atTotal: %v, choose: %v)", total, atTotal, choose))
}
```

## Other usages

### Advanced use cases with multiple ellipses

Standalone erasure coded configuration with 4 sets with 16 drives each, which spawns drives across controllers.

### Certificate Renewal { #certificate-renewal }

At some point in the future, each certificate would **expire** (about 3 months after acquiring it).

And then, there would be another program (in some cases it's another program, in some cases it could be the same TLS Termination Proxy) that would talk to Let's Encrypt, and renew the certificate(s).

   * this function.
   *
   * <p><b>Warning: do not depend</b> on the behavior of this method.
   *
   * <p>Historically, {@code Function} instances in this library have implemented this method to
   * recognize certain cases where distinct {@code Function} instances would in fact behave
   * identically. However, as code migrates to {@code java.util.function}, that behavior will
   * disappear. It is best not to depend on it.
   */
  @Override

Although any other parameter declared normally (for example, the body with a Pydantic model) would still be validated, converted, annotated, etc.

But there are specific cases where it's useful to get the `Request` object.

## Use the `Request` object directly { #use-the-request-object-directly }

Let's imagine you want to get the client's IP address/host inside of your *path operation function*.

You can combine normal FastAPI *path operations* with GraphQL on the same application.

/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.

Make sure you evaluate if the **benefits** for your use case compensate the **drawbacks**. 🤓

///

## GraphQL Libraries { #graphql-libraries }

  }

  /**
   * Override to return a chaining listenableFuture that returns the result of getSuccessfulResult()
   * when inputFuture returns VALID_INPUT_DATA, and sets the exception to EXCEPTION in all other
   * cases.
   */
  protected abstract ListenableFuture<T> buildChainingFuture(ListenableFuture<Integer> inputFuture);

  /**
   * Override to return the result when VALID_INPUT_DATA is passed in to the chaining

<img src="/img/tutorial/extending-openapi/image04.png">

## Change Default Swagger UI Parameters { #change-default-swagger-ui-parameters }

FastAPI includes some default configuration parameters appropriate for most of the use cases.

It includes these default configurations:

{* ../../fastapi/openapi/docs.py ln[9:24] hl[18:24] *}

You can override any of them by setting a different value in the argument `swagger_ui_parameters`.

/// info

A "bearer" token is not the only option.

But it's the best one for our use case.

And it might be the best for most use cases, unless you are an OAuth2 expert and know exactly why there's another option that better suits your needs.

In that case, **FastAPI** also provides you with the tools to build it.

///

		// Short; unchanged:
		{`C:\short.txt`, `C:\short.txt`},
		{`C:\`, `C:\`},
		{`C:`, `C:`},
		// The "long" substring is replaced by a looooooong
		// string which triggers the rewriting. Except in the
		// cases below where it doesn't.
		{`C:\long\foo.txt`, `\\?\C:\long\foo.txt`},
		{`C:/long/foo.txt`, `\\?\C:\long\foo.txt`},
		{`C:\long\foo\\bar\.\baz\\`, `\\?\C:\long\foo\bar\baz`},
		{`\\unc\path`, `\\unc\path`},

import com.google.common.testing.NullPointerTester;
import com.google.common.testing.SerializableTester;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Test cases for {@link HashBasedTable}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public class HashBasedTableTest extends AbstractTableTest<Character> {

  @Override