@Test
  fun requestHeaderValidationIsStrict() {
    assertFailsWith<IllegalArgumentException> {
      Request
        .Builder()
        .addHeader("a\tb", "Value")
    }
    assertFailsWith<IllegalArgumentException> {
      Request
        .Builder()
        .addHeader("Name", "c\u007fd")
    }
    assertFailsWith<IllegalArgumentException> {
      Request
        .Builder()

      V value = values.next();
      builder.put(keyFunction.apply(value), value);
    }
    try {
      return builder.buildOrThrow();
    } catch (IllegalArgumentException duplicateKeys) {
      throw new IllegalArgumentException(
          duplicateKeys.getMessage()
              + ". To index multiple values under a key, use Multimaps.index.");
    }
  }

  /**

      V value = values.next();
      builder.put(keyFunction.apply(value), value);
    }
    try {
      return builder.buildOrThrow();
    } catch (IllegalArgumentException duplicateKeys) {
      throw new IllegalArgumentException(
          duplicateKeys.getMessage()
              + ". To index multiple values under a key, use Multimaps.index.");
    }
  }

  /**

    assertFailsWith<IllegalArgumentException> {
      requestBuilder.url("ftp://hostname/path")
    }.also { expected ->
      assertThat(expected.message).isEqualTo("Expected URL scheme 'http' or 'https' but was 'ftp'")
    }
  }

  @Test
  fun invalidPort() {
    val requestBuilder = Request.Builder()
    assertFailsWith<IllegalArgumentException> {
      requestBuilder.url("http://localhost:65536/")