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      if (length == elements.length) {
        dedupAndCoalesce(true);
      } else if (forceCopyElements) {
        this.elements = Arrays.copyOf(elements, elements.length);
        // we don't currently need to copy the counts array, because we don't use it directly
        // in built ISMs
      }
      forceCopyElements = false;
    }

    private void dedupAndCoalesce(boolean maybeExpand) {
      if (length == 0) {

          return existing;
        }
      }
      drainQueue();
      return created;
    }

    // N.B. Draining the queue is only necessary to ensure that we don't accumulate empty references
    // in the array. We could skip this if we decide we don't care about holding on to Reference
    // objects indefinitely.
    private void drainQueue() {
      Reference<? extends L> ref;
      while ((ref = queue.poll()) != null) {

    assertThat(request.tag(String::class)).isSameAs(stringTag)

    // TODO check for Jvm or handle Long/long correctly
//    assertThat(request.tag(Long::class)).isSameAs(longTag)
  }

  /** Confirm that we don't accidentally share the backing map between objects. */
  @Test
  fun tagsAreImmutable() {
    val builder =
      Request.Builder()
        .url("https://square.com")

 *
 * This test only runs on host machines that have both IPv4 and IPv6 addresses for localhost.
 */
@Timeout(30)
class FastFallbackTest {
  @RegisterExtension
  val clientTestRule = OkHttpClientTestRule()

  // Don't use JUnit 5 test rules for these; otherwise we can't bind them to a single local IP.
  private lateinit var localhostIpv4: InetAddress
  private lateinit var localhostIpv6: InetAddress
  private lateinit var serverIpv4: MockWebServer