System.out.println("hit rate: " + hit / req);
  }

  // for proper distributions later:
  // import JSci.maths.statistics.ProbabilityDistribution;
  // int key = (int) dist.inverse(random.nextDouble());

import org.jspecify.annotations.Nullable;

/**
 * An object that converts literal text into a format safe for inclusion in a particular context
 * (such as an XML document). Typically (but not always), the inverse process of "unescaping" the
 * text is performed automatically by the relevant parser.
 *
 * <p>For example, an XML escaper would convert the literal string {@code "Foo<Bar>"} into {@code

import org.jspecify.annotations.Nullable;

/**
 * An {@link Escaper} that converts literal text into a format safe for inclusion in a particular
 * context (such as an XML document). Typically (but not always), the inverse process of
 * "unescaping" the text is performed automatically by the relevant parser.
 *
 * <p>For example, an XML escaper would convert the literal string {@code "Foo<Bar>"} into {@code

import org.jspecify.annotations.Nullable;

/**
 * An {@link Escaper} that converts literal text into a format safe for inclusion in a particular
 * context (such as an XML document). Typically (but not always), the inverse process of
 * "unescaping" the text is performed automatically by the relevant parser.
 *
 * <p>For example, an XML escaper would convert the literal string {@code "Foo<Bar>"} into {@code

  public abstract ImmutableCollection<V> get(K key);

  /**
   * Returns an immutable multimap which is the inverse of this one. For every key-value mapping in
   * the original, the result will have a mapping with key and value reversed.
   *
   * @since 11.0
   */
  public abstract ImmutableMultimap<V, K> inverse();

  /**
   * Guaranteed to throw an exception and leave the multimap unmodified.
   *

import com.google.errorprone.annotations.DoNotMock;

/**
 * An object that converts literal text into a format safe for inclusion in a particular context
 * (such as an XML document). Typically (but not always), the inverse process of "unescaping" the
 * text is performed automatically by the relevant parser.
 *
 * <p>For example, an XML escaper would convert the literal string {@code "Foo<Bar>"} into {@code

import java.io.ObjectOutputStream;
import java.util.EnumMap;
import java.util.Map;

/**
 * A {@code BiMap} backed by two {@code EnumMap} instances. Null keys and values are not permitted.
 * An {@code EnumBiMap} and its inverse are both serializable.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.
 *
 * @author Mike Bostock
 * @since 2.0
 */

/**
 * A {@code BiMap} backed by an {@code EnumMap} instance for keys-to-values, and a {@code HashMap}
 * instance for values-to-keys. Null keys are not permitted, but null values are. An {@code
 * EnumHashBiMap} and its inverse are both serializable.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.
 *
 * @author Mike Bostock
 * @since 2.0
 */

import org.jspecify.annotations.Nullable;

/**
 * An object that converts literal text into a format safe for inclusion in a particular context
 * (such as an XML document). Typically (but not always), the inverse process of "unescaping" the
 * text is performed automatically by the relevant parser.
 *
 * <p>For example, an XML escaper would convert the literal string {@code "Foo<Bar>"} into {@code

   * space character.
   *
   * <p>Not that it is allowed, but not necessarily desirable to specify {@code %} as a safe
   * character. This has the effect of creating an escaper which has no well-defined inverse but it
   * can be useful when escaping additional characters.
   *
   * @param safeChars a non-null string specifying additional safe characters for this escaper (the