/**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;

    /**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static java.util.Arrays.asList;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;

import static com.google.common.cache.CacheBuilder.UNSET_INT;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static com.google.common.util.concurrent.Futures.transform;
import static com.google.common.util.concurrent.MoreExecutors.directExecutor;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static java.util.Arrays.asList;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;

(double-press shift) or under the _Analyze_ menu.

We’ve included deprecated APIs in OkHttp 4.0 because they make migration easy. We will remove them
in a future release! If you’re skipping releases, it’ll be much easier if you upgrade to OkHttp 4.0
as an intermediate step.

#### Vars and Vals

 * types by using <a href="https://github.com/lukas-krecan/future-converter#java8-guava">{@code
 * net.javacrumbs.futureconverter.java8guava.FutureConverter}</a>.
 *
 * <h2>More on {@code CacheBuilder}</h2>
 *
 * {@code CacheBuilder} builds caches with any combination of the following features:
 *
 * <ul>
 *   <li>automatic loading of entries into the cache

    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */
    final Stack<E> nextElements = new Stack<>();

    /**
     * The elements to be returned by future calls to {@code previous()}, with the first at the top
     * of the stack.
     */

    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */
    final Stack<E> nextElements = new Stack<>();

    /**
     * The elements to be returned by future calls to {@code previous()}, with the first at the top
     * of the stack.
     */

    version of the library.

5.  Our classes are not designed to protect against a malicious caller. You
    should not use them for communication between trusted and untrusted code.

6.  For the mainline flavor, we test the libraries using OpenJDK 8, 11, and 17
    on Linux, with some additional testing on newer JDKs and on Windows. Some