}

    @Override
    protected Map<String, Object> createTestParam(int id) {
        fail(); // Unreachable
        return null;
    }

    @Override
    protected Map<String, Object> getUpdateMap() {
        fail(); // Unreachable
        return null;
    }

    @Override
    protected void testRead() {
        final Map<String, Object> searchBody = new HashMap<>();

  SingletonImmutableSet(E element) {
    this.element = Preconditions.checkNotNull(element);
  }

  @Override
  public int size() {
    return 1;
  }

  @Override
  public boolean contains(@Nullable Object target) {
    return element.equals(target);
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return singletonIterator(element);
  }

  @Override
  public ImmutableList<E> asList() {

    @SuppressWarnings("unchecked")
    @Override
    public BiMap<Country, String> create(Object... entries) {
      BiMap<Country, String> result = EnumHashBiMap.create(Country.class);
      for (Object o : entries) {
        Entry<Country, String> entry = (Entry<Country, String>) o;
        result.put(entry.getKey(), entry.getValue());
      }
      return result;

    }

    public void test_list_operations_with_metrics() {
        DocList docList = new DocList();

        Map<String, Object> doc1 = new HashMap<>();
        doc1.put("id", "1");
        doc1.put("title", "Test Document 1");

        Map<String, Object> doc2 = new HashMap<>();
        doc2.put("id", "2");
        doc2.put("title", "Test Document 2");

        docList.add(doc1);

    //                                                                              ======
    @Override
    public Map<String, Object> toSource() {
        Map<String, Object> sourceMap = new HashMap<>();
        if (createdBy != null) {
            addFieldToSource(sourceMap, "createdBy", createdBy);
        }
        if (createdTime != null) {

    //                                                                              ======
    @Override
    public Map<String, Object> toSource() {
        Map<String, Object> sourceMap = new HashMap<>();
        if (authRealm != null) {
            addFieldToSource(sourceMap, "authRealm", authRealm);
        }
        if (createdBy != null) {

        .testEquals();
  }

  public void testEquivalentTo() {
    Predicate<@Nullable Object> equalTo1 = Equivalence.equals().equivalentTo("1");
    assertTrue(equalTo1.apply("1"));
    assertFalse(equalTo1.apply("2"));
    assertFalse(equalTo1.apply(null));
    Predicate<@Nullable Object> isNull = Equivalence.equals().equivalentTo(null);
    assertFalse(isNull.apply("1"));
    assertFalse(isNull.apply("2"));

        .testEquals();
  }

  public void testEquivalentTo() {
    Predicate<@Nullable Object> equalTo1 = Equivalence.equals().equivalentTo("1");
    assertTrue(equalTo1.apply("1"));
    assertFalse(equalTo1.apply("2"));
    assertFalse(equalTo1.apply(null));
    Predicate<@Nullable Object> isNull = Equivalence.equals().equivalentTo(null);
    assertFalse(isNull.apply("1"));
    assertFalse(isNull.apply("2"));

    val latch = CountDownLatch(1)
    val exceptionRef = AtomicReference<Throwable>()
    val call = client.newCall(request)
    call.timeout().timeout(250, TimeUnit.MILLISECONDS)
    call.enqueue(
      object : Callback {
        override fun onFailure(
          call: Call,
          e: IOException,
        ) {
          exceptionRef.set(e)
          latch.countDown()
        }

   * returns an arbitrary (but consistent) endpoint of the origin edge.
   */
  public final N nodeU() {
    return nodeU;
  }

  /**
   * Returns the node {@link #adjacentNode(Object) adjacent} to {@link #nodeU()} along the origin
   * edge. If this {@link EndpointPair} {@link #isOrdered()}, this is equal to {@link #target()}.
   */
  public final N nodeV() {
    return nodeV;
  }

  /**