There are some extra features to handle security apart from the ones covered in the [Tutorial - User Guide: Security](../../tutorial/security/index.md){.internal-link target=_blank}.

/// tip

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

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

///

## Read the Tutorial first { #read-the-tutorial-first }

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.

///

## Read the Tutorial first { #read-the-tutorial-first }

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

You probably want to test the external provider once, but not necessarily call it for every test that runs.

In this case, you can override the dependency that calls that provider, and use a custom dependency that returns a mock user, only for your tests.

/// warning

Extra keys passed to `Field` will also be present in the resulting OpenAPI schema for your application.
As these keys may not necessarily be part of the OpenAPI specification, some OpenAPI tools, for example [the OpenAPI validator](https://validator.swagger.io/), may not work with your generated schema.

///

## Recap { #recap }

  ) {
  }

  /**
   * Invoked when a request fails to be written.
   *
   * This method is invoked after [requestHeadersStart] or [requestBodyStart]. Note that request
   * failures do not necessarily fail the entire call.
   */
  open fun requestFailed(
    call: Call,
    ioe: IOException,
  ) {
  }

  /**
   * Invoked when response headers are first returned from the server.
   *

import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * A skeleton {@code Multimap} implementation, not necessarily in terms of a {@code Map}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class AbstractMultimap<K extends @Nullable Object, V extends @Nullable Object>
    implements Multimap<K, V> {
  @Override

     * The Java tools location is {@link StandardLocation#CLASS_PATH}.
     *
     * <h4>Context-sensitive interpretation</h4>
     * A dependency with this path type will not necessarily be placed on the class path.
     * There are two circumstances where the dependency may nevertheless be placed somewhere else:
     *
     * <ul>

    val name = this.withLock { nextQueueName++ }
    return TaskQueue(this, "Q$name")
  }

  /**
   * Returns a snapshot of queues that currently have tasks scheduled. The task runner does not
   * necessarily track queues that have no tasks scheduled.
   */
  fun activeQueues(): List<TaskQueue> {
    this.withLock {
      return busyQueues + readyQueues
    }
  }

  fun cancelAll() {
    assertLockHeld()

/// warning

This is a more or less advanced section. If you are just starting, you can skip it.

You don't necessarily need OAuth2 scopes, and you can handle authentication and authorization however you want.

But OAuth2 with scopes can be nicely integrated into your API (with OpenAPI) and your API docs.

   * The order of the elements in the element set is unspecified.
   *
   * <p>If the element set supports any removal operations, these necessarily cause <b>all</b>
   * occurrences of the removed element(s) to be removed from the multiset. Implementations are not
   * expected to support the add operations, although this is possible.
   *