),
              "... contents of file2.gif ..."
                .toByteArray(StandardCharsets.UTF_8)
                .toRequestBody("image/gif".toMediaType()),
            ).build(),
        ).build()
    assertThat(body.boundary).isEqualTo("AaB03x")
    assertThat(body.type).isEqualTo(MultipartBody.FORM)
    assertThat(body.contentType().toString()).isEqualTo(
      "multipart/form-data; boundary=AaB03x",

    ImmutableList.Builder<String> httpHeaders = ImmutableList.builder();
    for (Field field : httpHeadersFields()) {
      httpHeaders.add((String) field.get(null));
    }
    assertThat(httpHeaders.build()).containsNoDuplicates();
  }

  private static ImmutableSet<Field> httpHeadersFields() {
    ImmutableSet.Builder<Field> builder = ImmutableSet.builder();

  public PreemptiveAuth() {
    client = new OkHttpClient.Builder()
        .addInterceptor(
            new BasicAuthInterceptor("publicobject.com", "jesse", "password1"))
        .build();
  }

  public void run() throws Exception {
    Request request = new Request.Builder()
        .url("https://publicobject.com/secrets/hellosecret.txt")
        .build();

    try (Response response = client.newCall(request).execute()) {

  }

  public static <K, V> Builder<K, V> builder() {
    return new Builder<K, V>();
  }

  public static final class Builder<K, V> extends ImmutableMap.Builder<K, V> {

    public Builder() {}

    Builder(int initCapacity) {
      super(initCapacity);
    }

    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> put(K key, V value) {
      super.put(key, value);

    throw new InvalidObjectException("Use SerializedForm");
  }

  /**
   * Returns a new builder. The generated builder is equivalent to the builder created by the {@link
   * Builder} constructor.
   */
  public static <E> Builder<E> builder() {
    return new Builder<>();
  }

  /**
   * A builder for creating immutable multiset instances, especially {@code public static final}

    return new RegularImmutableMap<>(entries);
  }

  public static <K, V> Builder<K, V> builder() {
    return new Builder<K, V>();
  }

  public static <K, V> Builder<K, V> builderWithExpectedSize(int expectedSize) {
    return new Builder<K, V>(expectedSize);
  }

  static <K, V> Entry<K, V> entryOf(K key, V value) {
    checkEntryNotNull(key, value);

    //                                                                               =====

    @Override
    public SearchRequestBuilder build(SearchRequestBuilder builder) {
        if (_conditionQuery != null) {
            QueryBuilder queryBuilder = _conditionQuery.getQuery();
            if (queryBuilder != null) {
                builder.setQuery(queryBuilder);
            }

    //                                                                               =====

    @Override
    public SearchRequestBuilder build(SearchRequestBuilder builder) {
        if (_conditionQuery != null) {
            QueryBuilder queryBuilder = _conditionQuery.getQuery();
            if (queryBuilder != null) {
                builder.setQuery(queryBuilder);
            }

    //                                                                               =====

    @Override
    public SearchRequestBuilder build(SearchRequestBuilder builder) {
        if (_conditionQuery != null) {
            QueryBuilder queryBuilder = _conditionQuery.getQuery();
            if (queryBuilder != null) {
                builder.setQuery(queryBuilder);
            }

    //                                                                               =====

    @Override
    public SearchRequestBuilder build(SearchRequestBuilder builder) {
        if (_conditionQuery != null) {
            QueryBuilder queryBuilder = _conditionQuery.getQuery();
            if (queryBuilder != null) {
                builder.setQuery(queryBuilder);
            }