T result = uncheckedCastNullableTToT(next);
    next = null;
    return result;
  }

  @Override
  public final void remove() {
    throw new UnsupportedOperationException();
  }

   * part of the smeared hash of the element not covered by the hashtable mask, whereas the low bits
   * are the "next" pointer (pointing to the next entry in the bucket chain), which will always be
   * less than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *

        assertThat(i.next(), is("bbb"));
        assertThat(i.next(), is("ccc"));
        assertThat(i.next(), is("aaa"));
        lru.put("ddd", "444");
        assertThat(lru.size(), is(3));
        assertThat(lru.get("bbb"), is(nullValue()));
        i = lru.keySet().iterator();
        assertThat(i.next(), is("ccc"));
        assertThat(i.next(), is("aaa"));
        assertThat(i.next(), is("ddd"));

   * part of the smeared hash of the key not covered by the hashtable mask, whereas the low bits are
   * the "next" pointer (pointing to the next entry in the bucket chain), which will always be less
   * than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *

    assertThrows(NoSuchElementException.class, () -> iterator.next());
    assertThrows(IllegalStateException.class, () -> iterable.iterator());
  }

  public void testOf_one() {
    Iterable<String> iterable = MinimalIterable.of("a");
    Iterator<String> iterator = iterable.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertFalse(iterator.hasNext());

  @SuppressWarnings("GoodTime") // b/122668874
  void setAccessTime(long time);

  /** Returns the next entry in the access queue. */
  ReferenceEntry<K, V> getNextInAccessQueue();

  /** Sets the next entry in the access queue. */
  void setNextInAccessQueue(ReferenceEntry<K, V> next);

  /** Returns the previous entry in the access queue. */
  ReferenceEntry<K, V> getPreviousInAccessQueue();

   */
  public abstract @Nullable C previous(C value);

  /**
   * Returns a signed value indicating how many nested invocations of {@link #next} (if positive) or
   * {@link #previous} (if negative) are needed to reach {@code end} starting from {@code start}.
   * For example, if {@code end = next(next(next(start)))}, then {@code distance(start, end) == 3}
   * and {@code distance(end, start) == -3}. As well, {@code distance(a, a)} is always zero.
   *

      return next != null;
    }

    @Override
    @ParametricNullness
    public K next() {
      checkForConcurrentModification();
      if (next == null) {
        throw new NoSuchElementException();
      }
      current = next;
      seenKeys.add(current.getKey());
      do { // skip ahead to next unseen key
        next = next.next;

      int initialSize = map.size();
      boolean didRemove = entrySet.remove(entrySet.iterator().next());
      assertTrue(didRemove);
      assertEquals(initialSize - 1, map.size());
    } else {
      assertThrows(
          UnsupportedOperationException.class, () -> entrySet.remove(entrySet.iterator().next()));
    }
    assertInvariants(map);
  }

  public void testEntrySetRemoveMissingKey() {

    final Runnable runnable;
    final Executor executor;
    @Nullable RunnableExecutorPair next;

    RunnableExecutorPair(
        Runnable runnable, Executor executor, @Nullable RunnableExecutorPair next) {
      this.runnable = runnable;
      this.executor = executor;
      this.next = next;
    }
  }