import java.util.Set;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReferenceArray;
import java.util.concurrent.locks.ReentrantLock;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * The concurrent hash map implementation built by {@link MapMaker}.
 *

   * 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 com.google.common.primitives.Longs;
import com.google.errorprone.annotations.concurrent.GuardedBy;
import com.google.j2objc.annotations.Weak;
import java.time.Duration;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import java.util.function.BooleanSupplier;
import org.jspecify.annotations.Nullable;

/**

import java.util.Arrays;
import java.util.Collections;
import java.util.EnumSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.CIFSContext;
import jcifs.CIFSException;
import jcifs.DfsReferralData;

import java.util.Set;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReferenceArray;
import java.util.concurrent.locks.ReentrantLock;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * The concurrent hash map implementation built by {@link MapMaker}.
 *

import java.net.InetAddress
import java.net.InetSocketAddress
import java.net.Proxy
import java.security.cert.X509Certificate
import java.util.Arrays
import java.util.concurrent.CountDownLatch
import java.util.concurrent.atomic.AtomicInteger
import java.util.concurrent.atomic.AtomicReference
import javax.net.ssl.HostnameVerifier
import javax.net.ssl.SSLPeerUnverifiedException
import javax.net.ssl.SSLSession

import java.util.Queue;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReferenceArray;
import java.util.concurrent.locks.ReentrantLock;
import java.util.function.BiFunction;

java.util.concurrent.ThreadPoolExecutor#<init>(int, int, long, java.util.concurrent.TimeUnit, java.util.concurrent.BlockingQueue, java.util.concurrent.RejectedExecutionHandler)
java.util.concurrent.ThreadPoolExecutor#<init>(int, int, long, java.util.concurrent.TimeUnit, java.util.concurrent.BlockingQueue, java.util.concurrent.ThreadFactory, java.util.concurrent.RejectedExecutionHandler)

    printEvent("callStart");
  }

  @Override public void callEnd(Call call) {
    printEvent("callEnd");
  }

  ...
}
```

We can use this listener to race a pair of concurrent HTTP requests:

```java
Request washingtonPostRequest = new Request.Builder()
    .url("https://www.washingtonpost.com/")
    .build();
client.newCall(washingtonPostRequest).enqueue(new Callback() {
  ...

import static com.google.common.util.concurrent.FuturesGetCheckedInputs.OTHER_THROWABLE;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.RUNTIME_EXCEPTION;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.RUNTIME_EXCEPTION_FUTURE;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.UNCHECKED_EXCEPTION;