this.allowsNullKeys = allowsNullKeys;
    this.allowsNullValues = allowsNullValues;
    this.supportsIteratorRemove = supportsIteratorRemove;
  }

  /**
   * Used by tests that require a map, but don't care whether it's populated or not.
   *
   * @return a new map instance.
   */
  protected Map<K, V> makeEitherMap() {
    try {
      return makePopulatedMap();

    byte[] b = ByteStreams.toByteArray(in);
    assertThat(b).isEqualTo(new byte[0]);
  }

  public void testToByteArray_largeStream() throws IOException {
    // well, large enough to require multiple buffers
    byte[] expected = newPreFilledByteArray(10000000);
    InputStream in = new ByteArrayInputStream(expected);
    byte[] b = ByteStreams.toByteArray(in);
    assertThat(b).isEqualTo(expected);
  }

  /**
   * Runs Runnable r with a security policy that permits precisely the specified permissions. If
   * there is no current security manager, the runnable is run twice, both with and without a
   * security manager. We require that any security manager permit getPolicy/setPolicy.
   */
  public void runWithPermissions(Runnable r, Permission... permissions) {
    SecurityManager sm = System.getSecurityManager();
    if (sm == null) {

      TypeVariable<?>[] typeVars = rawType.getTypeParameters();
      for (int i = 0; i < params.size(); i++) {
        TypeToken<?> paramType = type.resolveType(typeVars[i]);
        // We require all @Generates methods to either be parameter-less or accept non-null
        // values for their generic parameter types.
        Object argValue = generate(paramType);
        if (argValue == null) {

   * 0}.
   *
   * @throws IllegalArgumentException if {@code a < 0} or {@code b < 0}
   */
  public static int gcd(int a, int b) {
    /*
     * The reason we require both arguments to be >= 0 is because otherwise, what do you return on
     * gcd(0, Integer.MIN_VALUE)? BigInteger.gcd would return positive 2^31, but positive 2^31 isn't
     * an int.
     */
    checkNonNegative("a", a);

      // extra zero bits we need to add to the end of bitsPerChar to get 3 in total.
      // The logic here would be wrong for bitsPerChar > 8, but since we require distinct ASCII
      // characters that can't happen.
      int zeroesInBitsPerChar = Integer.numberOfTrailingZeros(bitsPerChar);
      this.charsPerChunk = 1 << (3 - zeroesInBitsPerChar);

  }

  /**
   * Returns true if the given member is a method that overrides {@link Object#equals(Object)}.
   *
   * <p>The documentation for {@link Object#equals} says it should accept null, so don't require an
   * explicit {@code @Nullable} annotation (see <a
   * href="https://github.com/google/guava/issues/1819">#1819</a>).
   *

    @Retention(RetentionPolicy.RUNTIME)
    @Inherited
    @TesterAnnotation
    @interface Require {
      ExampleDerivedFeature[] value() default {};

      ExampleDerivedFeature[] absent() default {};
    }
  }

  @Retention(RetentionPolicy.RUNTIME)
  @interface NonTesterAnnotation {}

  @ExampleBaseFeature.Require({ExampleBaseFeature.BASE_FEATURE_1})

 *       {@link #poll} and {@link #remove()}) run in {@code O(log n) time}.
 *   <li>The {@link #remove(Object)} and {@link #contains} operations require linear ({@code O(n)})
 *       time.
 *   <li>If you only access one end of the queue, and don't use a maximum size, this class is
 *       functionally equivalent to {@link PriorityQueue}, but significantly slower.
 * </ul>

   *       (In simple cases, callers can avoid this by registering all tasks with the same {@link
   *       MoreExecutors#newSequentialExecutor} wrapper around {@code directExecutor()}. More
   *       complex cases may require using thread pools or making deeper changes.)
   *   <li>If an exception propagates out of a {@code Runnable}, it is not necessarily seen by any