cycle.remove();
    assertEquals(singletonList("b"), iterable);
    assertTrue(cycle.hasNext());
    assertEquals("b", cycle.next());
    assertTrue(cycle.hasNext());
    assertEquals("b", cycle.next());
    cycle.remove();
    assertEquals(emptyList(), iterable);
    assertFalse(cycle.hasNext());
  }

  public void testCycleRemoveWithoutNext() {
    Iterator<String> cycle = Iterators.cycle("a", "b");

            List<String> cycle = visitCycle(graph, Collections.singleton(to), new HashMap<>(), new LinkedList<>());
            if (cycle != null) {
                // remove edge which introduced cycle
                throw new CycleDetectedException(
                        "Edge between '" + from + "' and '" + to + "' introduces to cycle in the graph", cycle);
            }
        }
    }

    cycle.remove();
    assertEquals(singletonList("b"), iterable);
    assertTrue(cycle.hasNext());
    assertEquals("b", cycle.next());
    assertTrue(cycle.hasNext());
    assertEquals("b", cycle.next());
    cycle.remove();
    assertEquals(emptyList(), iterable);
    assertFalse(cycle.hasNext());
  }

  public void testCycleRemoveWithoutNext() {
    Iterator<String> cycle = Iterators.cycle("a", "b");

        from.children.add(to);
        to.parents.add(from);
        List<String> cycle = findCycle(to);
        if (cycle != null) {
            // remove edge which introduced cycle
            removeEdge(from, to);
            throw new CycleDetectedException(
                    "Edge between '" + from.label + "' and '" + to.label + "' introduces to cycle in the graph", cycle);
        }
    }

    void removeEdge(Vertex from, Vertex to) {

    // always point to "a".
    assertEquals("a", cycle.iterator().next());
  }

  public void testCycle_emptyIterable() {
    FluentIterable<Integer> cycle = FluentIterable.<Integer>of().cycle();
    assertFalse(cycle.iterator().hasNext());
  }

  public void testCycle_removingAllElementsStopsCycle() {
    FluentIterable<Integer> cycle = fluent(1, 2).cycle();
    Iterator<Integer> iterator = cycle.iterator();

	minSleep time.Duration

	// cycle will be closed
	cycle chan struct{}

	// isScanner should be set when this is used by the scanner
	// to record metrics.
	isScanner bool
}

// newDynamicSleeper
func newDynamicSleeper(factor float64, maxWait time.Duration, isScanner bool) *dynamicSleeper {
	return &dynamicSleeper{
		factor:    factor,
		cycle:     make(chan struct{}),
		maxSleep:  maxWait,

       *
       * Maybe there is a way to avoid this cycle. But we think the cycle is safe enough to ignore:
       * Each task is retained for only as long as it is running -- so it's retained only as long as
       * it would already be retained by the underlying executor.
       *
       * If the cycle test starts reporting this cycle in the future, we should add an entry to
       * cycle_suppress_list.txt.
       */

  }

  public void testConcat_infiniteIterable() throws IOException {
    CharSource source = CharSource.wrap("abcd");
    Iterable<CharSource> cycle = Iterables.cycle(ImmutableList.of(source));
    CharSource concatenated = CharSource.concat(cycle);

    String expected = "abcdabcd";

    // read the first 8 chars manually, since there's no equivalent to ByteSource.slice

}

// mod returns true if the hash mod cycles == cycle.
// If cycles is 0 false is always returned.
// If cycles is 1 true is always returned (as expected).
func (h dataUsageHash) mod(cycle uint32, cycles uint32) bool {
	if cycles <= 1 {
		return cycles == 1
	}
	return uint32(xxhash.Sum64String(string(h)))%cycles == cycle%cycles
}

// modAlt returns true if the hash mod cycles == cycle.
// This is out of sync with mod.

  }

  public void testConcat_infiniteIterable() throws IOException {
    ByteSource source = ByteSource.wrap(new byte[] {0, 1, 2, 3});
    Iterable<ByteSource> cycle = Iterables.cycle(ImmutableList.of(source));
    ByteSource concatenated = ByteSource.concat(cycle);

    byte[] expected = {0, 1, 2, 3, 0, 1, 2, 3};
    assertArrayEquals(expected, concatenated.slice(0, 8).read());
  }