*
 * <p>This class has limited support for cancellation and other "early completions":
 *
 * <ul>
 *   <li>While calls to {@code submit} and {@code submitAsync} return a {@code Future} that can be
 *       cancelled, cancellation never propagates to a task that has started to run -- neither to
 *       the callable itself nor to any {@code Future} returned by an {@code AsyncCallable}.

   * necessarily indicate application-layer success: `response` may still indicate an unhappy HTTP
   * response code like 404 or 500.
   *
   * @throws IOException if the request could not be executed due to cancellation, a connectivity
   *     problem or timeout. Because networks can fail during an exchange, it is possible that the
   *     remote server accepted the request before the failure.

 * earliest one wins. This applies to both executions scheduled with [TaskRunner.Queue.schedule] and
 * those implied by the returned execution delay.
 *
 * Cancellation
 * ------------
 *
 * Tasks may be canceled while they are waiting to be executed, or while they are executing.
 *
 * Canceling a task that is waiting to execute prevents that upcoming execution. Canceling a task

import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/** Tests for {@link AbstractFuture} with the cancellation cause system property set */
@AndroidIncompatible // custom classloading

@NullUnmarked
public class AbstractFutureCancellationCauseTest extends TestCase {

  private ClassLoader oldClassLoader;

import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/** Tests for {@link AbstractFuture} with the cancellation cause system property set */
@AndroidIncompatible // custom classloading

@NullUnmarked
public class AbstractFutureCancellationCauseTest extends TestCase {

  private ClassLoader oldClassLoader;

  /**
   * Tests that a canceled future throws a cancellation exception.
   *
   * <p>This method checks the cancel, isCancelled, and isDone methods.
   */
  public void testCanceledFutureThrowsCancellation() throws Exception {

    assertFalse(future.isDone());
    assertFalse(future.isCancelled());

    CountDownLatch successLatch = new CountDownLatch(1);

    // Run cancellation in a separate thread as an extra thread-safety test.

     * All elements of `futures` are completed, or this future has already completed and read
     * `futures` into a local variable (in preparation for propagating cancellation to them). In
     * either case, no one needs to read `futures` for cancellation purposes later. (And
     * cancellation purposes are the main reason to access `futures`, as discussed in its docs.)
     */
    this.futures = null;
  }

  enum ReleaseResourcesReason {

  }
}
```

This is implemented using `suspendCancellableCoroutine`
but uses the standard Dispatcher in OkHttp. This means
that by default Kotlin's Dispatchers are not used.

Cancellation if implemented sensibly in both directions.
Cancelling a coroutine scope, will cancel the call.
Cancelling a call, will throw a CancellationException

  /**
   * Tests that a canceled future throws a cancellation exception.
   *
   * <p>This method checks the cancel, isCancelled, and isDone methods.
   */
  public void testCanceledFutureThrowsCancellation() throws Exception {

    assertFalse(future.isDone());
    assertFalse(future.isCancelled());

    CountDownLatch successLatch = new CountDownLatch(1);

    // Run cancellation in a separate thread as an extra thread-safety test.

type Store interface {
	// New creates a new Stmt object and caches it.
	// Parameters:
	//   ctx: The context for the request, which can carry deadlines, cancellation signals, etc.
	//   key: The key representing the SQL query, used for caching and preparing the statement.
	//   isTransaction: Indicates whether this operation is part of a transaction, which may affect the caching strategy.