import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import org.jspecify.annotations.Nullable;

/**
 * A TimeLimiter implementation which actually does not attempt to limit time at all. This may be
 * desirable to use in some unit tests. More importantly, attempting to debug a call which is

public abstract class ForwardingSortedMap<K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingMap<K, V> implements SortedMap<K, V> {
  // TODO(lowasser): identify places where thread safety is actually lost

  /** Constructor for use by subclasses. */
  protected ForwardingSortedMap() {}

  @Override
  protected abstract SortedMap<K, V> delegate();

  @Override

     * comment: Does it send mock mail? (true: no send actually, logging only)
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getMailSendMock();

    /**
     * Is the property for the key 'mail.send.mock' true? <br>
     * The value is, e.g. true <br>
     * comment: Does it send mock mail? (true: no send actually, logging only)

    try {
      assertEquals(0, Queues.drain(q, ImmutableList.of(), 0, 10, MILLISECONDS));
    } catch (InterruptedException e) {
      throw new AssertionError();
    }

    // but does the wait actually occurs?
    @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
    Future<?> possiblyIgnoredError = threadPool.submit(new Interrupter(currentThread()));
    try {

`Header` is a "sister" class of `Path`, `Query` and `Cookie`. It also inherits from the same common `Param` class.

But remember that when you import `Query`, `Path`, `Header`, and others from `fastapi`, those are actually functions that return special classes.

///

/// info

To declare headers, you need to use `Header`, because otherwise the parameters would be interpreted as query parameters.

///

 * possible sequences of these operations, up to a given number of steps. So, if the caller
 * specifies to use <i>n</i> steps, a total of <i>3^n</i> tests are actually performed.
 *
 * <p>For instance, if <i>steps</i> is 5, one example sequence that will be tested is:
 *
 * <ol>
 *   <li>remove();
 *   <li>hasNext()
 *   <li>hasNext();
 *   <li>remove();
 *   <li>next();

  }

  interface A {}

  interface B {}

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(newDelegatingList(LIST1))
        // Actually, this violates List#equals contract.
        // But whatever, no one is going to proxy List (hopefully).
        .addEqualityGroup(newDelegatingList(LIST1))
        .addEqualityGroup(newDelegatingList(LIST2))

And of course, it supports the same:

* data validation
* data serialization
* data documentation, etc.

This works the same way as with Pydantic models. And it is actually achieved in the same way underneath, using Pydantic.

/// info

Keep in mind that dataclasses can't do everything Pydantic models can do.

So, you might still need to use Pydantic models.

It is also built to work as a future reference so you can come back and see exactly what you need.

## Run the code { #run-the-code }

All the code blocks can be copied and used directly (they are actually tested Python files).

To run any of the examples, copy the code to a file `main.py`, and start `fastapi dev`:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev

        registration.updateHeartbeat();

        // After update, should not be expired with long timeout
        assertFalse(registration.isExpired(60000));

        // Verify heartbeat was actually updated
        assertTrue(registration.getLastHeartbeat() > initialTime);
    }

    @Test
    void testExpiration() throws InterruptedException {