* write.
   *
   * 2. visibility of the writes to an afterDone() call triggered by cancel():
   *
   * Since these fields are non-final that means that TimeoutFuture is not being 'safely published',
   * thus a motivated caller may be able to expose the reference to another thread that would then
   * call cancel() and be unable to cancel the delegate.

    Stream<String> concatenated =
        Streams.concat(Stream.of("a"), streamB, Stream.empty(), Stream.of("c", "d"));
    assertThat(concatenated).containsExactly("a", "b", "c", "d").inOrder();
    concatenated.close();
    assertThat(closeCountB.get()).isEqualTo(1);
  }

  public void testConcat_refStream_closeIsPropagated_Stream_concat() {
    // Just to demonstrate behavior of Stream::concat in the standard library

    public final void addListener(Runnable listener, Executor executor) {
      super.addListener(listener, executor);
    }

    @CanIgnoreReturnValue
    @Override
    public final boolean cancel(boolean mayInterruptIfRunning) {
      return super.cancel(mayInterruptIfRunning);
    }
  }

  private static final Logger log = Logger.getLogger(AbstractFuture.class.getName());

  private State state;
  private V value;

  }

  private static void doTestSuccessfulAsList_resultCancelledRacingInputDone() throws Exception {
    // Simple (combined.cancel -> input.cancel -> setOneValue):
    successfulAsList(ImmutableList.of(SettableFuture.create())).cancel(true);

    /*
     * Complex (combined.cancel -> input.cancel -> other.set -> setOneValue),
     * to show that this isn't just about problems with the input future we just
     * cancelled:

      Character[] prefix = {Character.MIN_VALUE, Character.MAX_VALUE};
      Character[] suffix = {(char) 86, (char) 99};
      Character[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Character[] concat(Character[] left, Character[] right) {
    Character[] result = new Character[left.length + right.length];

      Double[] prefix = {Double.MIN_VALUE, Double.MAX_VALUE};
      Double[] suffix = {(double) 86, (double) 99};
      Double[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Double[] concat(Double[] left, Double[] right) {
    Double[] result = new Double[left.length + right.length];
    System.arraycopy(left, 0, result, 0, left.length);

      Character[] prefix = {Character.MIN_VALUE, Character.MAX_VALUE};
      Character[] suffix = {(char) 86, (char) 99};
      Character[] all = concat(concat(prefix, elements), suffix);
      return asList(all).subList(2, elements.length + 2);
    }
  }

  private static Character[] concat(Character[] left, Character[] right) {
    Character[] result = new Character[left.length + right.length];

    String expected = "abcde";

    assertEquals(expected, CharSource.concat(ImmutableList.of(c1, c2, c3)).read());
    assertEquals(expected, CharSource.concat(c1, c2, c3).read());
    assertEquals(expected, CharSource.concat(ImmutableList.of(c1, c2, c3).iterator()).read());
    assertFalse(CharSource.concat(c1, c2, c3).isEmpty());

    CharSource emptyConcat = CharSource.concat(CharSource.empty(), CharSource.empty());

    assertArrayEquals(expected, ByteSource.concat(ImmutableList.of(b1, b2, b3)).read());
    assertArrayEquals(expected, ByteSource.concat(b1, b2, b3).read());
    assertArrayEquals(expected, ByteSource.concat(ImmutableList.of(b1, b2, b3).iterator()).read());
    assertEquals(expected.length, ByteSource.concat(b1, b2, b3).size());
    assertFalse(ByteSource.concat(b1, b2, b3).isEmpty());

    assertThat(Bytes.concat()).isEqualTo(EMPTY);
    assertThat(Bytes.concat(EMPTY)).isEqualTo(EMPTY);
    assertThat(Bytes.concat(EMPTY, EMPTY, EMPTY)).isEqualTo(EMPTY);
    assertThat(Bytes.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Bytes.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Bytes.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);
    assertThat(Bytes.concat(ARRAY1, ARRAY1, ARRAY1))