assertEquals("b", consumingIterator.next());
    assertThat(list).isEmpty();

    assertFalse(consumingIterator.hasNext());
  }

  @GwtIncompatible // ?
  // TODO: Figure out why this is failing in GWT.
  public void testConsumingIterator_duelingIterators() {
    // Test data
    List<String> list = Lists.newArrayList("a", "b");

    // Test & Verify

   * nodes. This is an O(n) operation in the common case (and O(n^2) in the worst), but we are saved
   * by two things.
   *
   * <ul>
   *   <li>This is only called when a waiting thread times out or is interrupted. Both of which
   *       should be rare.
   *   <li>The waiters list should be very short.
   * </ul>
   */
  private void removeWaiter(Waiter node) {

     * determined experimentally to match our desired probability of false positives.
     */
    // NB: yes, this is surprisingly high, but that's what the experiments said was necessary
    // Raising this number slows the worst-case contains behavior, speeds up hashFloodingDetected,
    // and reduces the false-positive probability.
    static final int MAX_RUN_MULTIPLIER = 13;

    /**

import static com.google.common.collect.Maps.immutableEntry;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.MoreExecutors.listeningDecorator;
import static java.lang.Thread.State.WAITING;
import static java.util.concurrent.Executors.newSingleThreadExecutor;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.MINUTES;

import static com.google.common.collect.Maps.immutableEntry;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.MoreExecutors.listeningDecorator;
import static java.lang.Thread.State.WAITING;
import static java.util.concurrent.Executors.newSingleThreadExecutor;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.MINUTES;

    assertEquals("b", consumingIterator.next());
    assertThat(list).isEmpty();

    assertFalse(consumingIterator.hasNext());
  }

  @GwtIncompatible // ?
  // TODO: Figure out why this is failing in GWT.
  public void testConsumingIterable_duelingIterators() {
    // Test data
    List<String> list = Lists.newArrayList(asList("a", "b"));

    // Test & Verify

   * @param unit a {@code TimeUnit} determining how to interpret the timeout parameter
   * @return the number of elements transferred
   * @throws InterruptedException if interrupted while waiting
   */
  @CanIgnoreReturnValue
  @J2ktIncompatible
  @GwtIncompatible // BlockingQueue
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  public static <E> int drain(

                   Why? At some point, presumably after
                   https://github.com/google/guava/commit/e06a8cec65815599e510d7f9c1ea9d2a8eaa438a,
                   builds with JDK8 began failing animal-sniffer with the error:

                   Failed to check signatures: Bad class file .../CollectionFuture$ListFuture.class

                   One way of dealing with that would be to disable

    } catch (NullPointerException expected) {
    }
    ImmutableList<String> result = builder.build();

    /*
     * Maybe it rejects all elements, or maybe it adds "a" before failing.
     * Either way is fine with us.
     */
    if (result.isEmpty()) {
      return;
    }
    assertTrue(ImmutableList.of("a").equals(result));
    assertEquals(1, result.size());
  }

    assertEquals("b", consumingIterator.next());
    assertThat(list).isEmpty();

    assertFalse(consumingIterator.hasNext());
  }

  @GwtIncompatible // ?
  // TODO: Figure out why this is failing in GWT.
  public void testConsumingIterable_duelingIterators() {
    // Test data
    List<String> list = Lists.newArrayList(asList("a", "b"));

    // Test & Verify