*     iterator().next()} or {@link Iterables#getFirst} instead.
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final Optional<@NonNull E> first() {
    Iterator<E> iterator = getDelegate().iterator();
    return iterator.hasNext() ? Optional.of(iterator.next()) : Optional.absent();
  }

  /**

   * of the transitive closure of {@code graph}. In other words, the returned {@link Graph} will not
   * be updated after modifications to {@code graph}.
   *
   * @since NEXT
   */
  // TODO(b/31438252): Consider optimizing for undirected graphs.
  public static <N> ImmutableGraph<N> transitiveClosure(
      Graph<N> graph, TransitiveClosureSelfLoopStrategy strategy) {

        Object result = data.getDataMap().get("list");
        assertNotNull(result);
        assertTrue(result instanceof List);

        // Test Set interface (should use iterator().next())
        Set<BsUser> set = new HashSet<>();
        set.add(entity1);
        set.add(entity2);
        RenderDataUtil.register(data, "set", set);

        Object setResult = data.getDataMap().get("set");

        circuitBreaker.tripBreaker();
        assertEquals(SimpleCircuitBreaker.State.OPEN, circuitBreaker.getState());

        // Wait for timeout
        Thread.sleep(150);

        // Next call should transition to HALF_OPEN
        String result = circuitBreaker.call(() -> "success");
        assertEquals("success", result);
        assertEquals(SimpleCircuitBreaker.State.HALF_OPEN, circuitBreaker.getState());

		select {
		case <-ctx.Done():
			return
		case <-monitor.C:
			if serverDebugLog {
				console.Debugln("running drive monitoring")
			}

			s.connectDisks(true)

			// Reset the timer for next interval
			monitor.Reset(monitorInterval)
		}
	}
}

func (s *erasureSets) GetLockers(setIndex int) func() ([]dsync.NetLocker, string) {
	return func() ([]dsync.NetLocker, string) {

    void testGetNextResponse() {
        // When
        CommonServerMessageBlockResponse nextResponse = response.getNextResponse();

        // Then - should return null as no next response is set
        assertEquals(null, nextResponse);
    }

    @Test
    @DisplayName("Should handle prepare method correctly")
    void testPrepareMethod() {
        // Given

      assertThat(drained).isAtMost(1);

      assertThat(timer.elapsed(MILLISECONDS)).isAtLeast(10L);

      // If even the first one wasn't there, clean up so that the next test doesn't see an element.
      producerThread.cancel(true);
      producer.doneProducing.await();
      if (drained == 0) {
        q.poll(); // not necessarily there if producer was interrupted
      }
    }

    private boolean isBroadcastAddress(final InetAddress svr) {
        return svr.equals(this.baddr) || svr.getAddress()[3] == (byte) 0xFF;
    }

    /**
     * Switches to the next available WINS server in round-robin fashion.
     *
     * @return the next WINS server address, or null if no WINS servers are configured
     */
    protected InetAddress switchWINS() {

              || !fitsInLong(BigIntegerMath.binomial(LongMath.biggestBinomials[k] + 1, k)));
      // In the first case, any long is valid; in the second, we want to test that the next-bigger
      // long overflows.
    }
    int k = LongMath.biggestBinomials.length;
    assertFalse(fitsInLong(BigIntegerMath.binomial(2 * k, k)));

        if (graphResult.hasErrors()) {
            return addExceptionToResult(
                    result, graphResult.getProblems().iterator().next().getException());
        }

        try {
            session.setProjectMap(getProjectMap(session.getProjects()));
        } catch (DuplicateProjectException e) {
            return addExceptionToResult(result, e);