* while other events occur sequentially; cancels may occur concurrently with other events. For
   * example, thread A may be executing [responseBodyStart] while thread B executes [canceled].
   * Implementations must support such concurrent calls.
   *
   * Note that cancellation is best-effort and that a call may proceed normally after it has been

import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Unit test for {@link FakeTicker}.
 *
 * @author Jige Yu
 */
@GwtCompatible

  fun headers(): Headers = headers

  /**
   * Returns the trailers after the HTTP response, which may be empty. This blocks until the
   * trailers are available to read.
   *
   * It is not safe to call this concurrently with code that is processing the response body. If you
   * call this without consuming the complete response body, any remaining bytes in the response
   * body will be discarded before trailers are returned.
   *

  /**
   * A plan holds either an immediately-usable connection, or one that must be connected first.
   * These steps are split so callers can call [connectTcp] on a background thread if attempting
   * multiple plans concurrently.
   */
  interface Plan {
    val isReady: Boolean

    fun connectTcp(): ConnectResult

    fun connectTlsEtc(): ConnectResult

    fun handleSuccess(): RealConnection

    fun cancel()

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@code Futures#withTimeout}.
 *

 * resulting XML document is parsed, the parser API will return this text as the original literal
 * string {@code "Foo<Bar>"}.
 *
 * <p>A {@code CharEscaper} instance is required to be stateless, and safe when used concurrently by
 * multiple threads.
 *
 * <p>Popular escapers are defined as constants in classes like {@link
 * com.google.common.html.HtmlEscapers} and {@link com.google.common.xml.XmlEscapers}. To create

   *
   * Note about volatile: volatile doesn't make it safe to read from a mutable graph in one thread
   * while writing to it in another. All it does is help with _reading_ from multiple threads
   * concurrently. For more information, see AbstractNetworkTest.concurrentIteration.
   */
  private transient volatile @Nullable Entry<K, V> cacheEntry;

  MapIteratorCache(Map<K, V> backingMap) {

 * since an iteration across all row keys occurs.
 *
 * <p>Note that this implementation is not synchronized. If multiple threads access this table
 * concurrently and one of the threads modifies the table, it must be synchronized externally.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#table">{@code Table}</a>.

 * since an iteration across all row keys occurs.
 *
 * <p>Note that this implementation is not synchronized. If multiple threads access this table
 * concurrently and one of the threads modifies the table, it must be synchronized externally.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#table">{@code Table}</a>.

   * [RequestBody.writeTo] after that method returns. For duplex requests bodies that condition is
   * lifted. Such writes occur on an application-provided thread and may occur concurrently with
   * reads of the [ResponseBody]. For duplex request bodies, [writeTo] should return
   * quickly, possibly by handing off the provided request body to another thread to perform
   * writing.
   *