import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.SampleElements.Colliders;
import java.util.List;
import org.jspecify.annotations.NullMarked;

/**
 * A generator using sample elements whose hash codes all collide badly.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public abstract class TestCollidingSetGenerator implements TestSetGenerator<Object> {
  @Override

import com.google.common.collect.testing.TestContainerGenerator;
import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates bimaps, containing sample entries, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public interface TestBiMapGenerator<K extends @Nullable Object, V extends @Nullable Object>

import java.util.Collection;
import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates multimaps, containing sample elements, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public interface TestMultimapGenerator<
        K extends @Nullable Object, V extends @Nullable Object, M extends Multimap<K, V>>

import java.util.Collection;
import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates multimaps, containing sample elements, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public interface TestMultimapGenerator<
        K extends @Nullable Object, V extends @Nullable Object, M extends Multimap<K, V>>

import com.google.common.annotations.GwtCompatible;
import java.util.SortedSet;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates sorted sets, containing sample elements, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public interface TestSortedSetGenerator<E extends @Nullable Object> extends TestSetGenerator<E> {
  @Override

import com.google.common.annotations.GwtCompatible;
import java.util.SortedSet;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates sorted sets, containing sample elements, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public interface TestSortedSetGenerator<E extends @Nullable Object> extends TestSetGenerator<E> {
  @Override

import com.google.common.collect.testing.SampleElements.Unhashables;
import java.util.Collection;
import java.util.List;
import org.jspecify.annotations.NullMarked;

/**
 * Creates collections containing unhashable sample elements, to be tested.
 *
 * @author Regina O'Dell
 */
@GwtCompatible
@NullMarked
public abstract class TestUnhashableCollectionGenerator<T extends Collection<UnhashableObject>>

    return Math.sqrt(populationVariance());
  }

  /**
   * Returns the <a href="http://en.wikipedia.org/wiki/Variance#Sample_variance">unbiased sample
   * variance</a> of the values. If this dataset is a sample drawn from a population, this is an
   * unbiased estimator of the population variance of the population. The count must be greater than
   * one.
   *

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.sample;

import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;
import com.squareup.moshi.Types;
import java.util.Collections;
import java.util.List;
import okhttp3.OkHttpClient;
import okhttp3.Request;

![Events Diagram](../assets/images/******@****.***)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java