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))

    assertEquals("d", itr2.next());
    assertEquals("c", itr2.next());
  }

  public void testConcatPartiallyAdvancedFirst() {
    Iterator<String> itr1 = Iterators.concat(singletonIterator("a"), Iterators.forArray("b", "c"));
    assertEquals("a", itr1.next());
    assertEquals("b", itr1.next());
    Iterator<String> itr2 = Iterators.concat(itr1, singletonIterator("d"));

      sources.add(newByteSource(start, span));
      start += span;
    }
    ByteSource joined = ByteSource.concat(sources);
    assertTrue(newByteSource(0, start).contentEquals(joined));
  }

  public void testReadSingleByte() throws Exception {
    ByteSource source = newByteSource(0, 10);
    ByteSource joined = ByteSource.concat(source, source);
    assertEquals(20, joined.size());
    InputStream in = joined.openStream();

  }

  public void testConcat() {
    assertThat(Doubles.concat()).isEqualTo(EMPTY);
    assertThat(Doubles.concat(EMPTY)).isEqualTo(EMPTY);
    assertThat(Doubles.concat(EMPTY, EMPTY, EMPTY)).isEqualTo(EMPTY);
    assertThat(Doubles.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Doubles.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Doubles.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);

  public void testConcat() {
    assertThat(Booleans.concat()).isEqualTo(EMPTY);
    assertThat(Booleans.concat(EMPTY)).isEqualTo(EMPTY);
    assertThat(Booleans.concat(EMPTY, EMPTY, EMPTY)).isEqualTo(EMPTY);
    assertThat(Booleans.concat(ARRAY_FALSE)).isEqualTo(ARRAY_FALSE);
    assertThat(Booleans.concat(ARRAY_FALSE)).isNotSameInstanceAs(ARRAY_FALSE);
    assertThat(Booleans.concat(EMPTY, ARRAY_FALSE, EMPTY)).isEqualTo(ARRAY_FALSE);

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

   * iterator supports it.
   *
   * <p><b>Java 8+ users:</b> The {@code Stream} equivalent of this method is {@code
   * Stream.concat(a, b)}.
   */
  public static <T extends @Nullable Object> Iterable<T> concat(
      Iterable<? extends T> a, Iterable<? extends T> b) {
    return FluentIterable.concat(a, b);
  }

  /**
   * Combines three iterables into a single iterable. The returned iterable has an iterator that

    assertEquals("d", itr2.next());
    assertEquals("c", itr2.next());
  }

  public void testConcatPartiallyAdvancedFirst() {
    Iterator<String> itr1 = Iterators.concat(singletonIterator("a"), Iterators.forArray("b", "c"));
    assertEquals("a", itr1.next());
    assertEquals("b", itr1.next());
    Iterator<String> itr2 = Iterators.concat(itr1, singletonIterator("d"));

  }

  public void testConcat() {
    assertThat(Doubles.concat()).isEqualTo(EMPTY);
    assertThat(Doubles.concat(EMPTY)).isEqualTo(EMPTY);
    assertThat(Doubles.concat(EMPTY, EMPTY, EMPTY)).isEqualTo(EMPTY);
    assertThat(Doubles.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Doubles.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Doubles.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);

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