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

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

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

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

    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

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

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

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

  private static Byte[] concat(Byte[] left, Byte[] right) {
    Byte[] result = new Byte[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];

      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];

      Double[] suffix = {86.0, 99.0};
      Double[] all = concat(concat(prefix, elements), suffix);
      return makeArray(all).subArray(2, elements.length + 2).asList();
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // used only from suite
  private static Double[] concat(Double[] a, Double[] b) {
    return ObjectArrays.concat(a, b, Double.class);
  }

  @J2ktIncompatible