*
   * @throws IOException if an I/O error occurs while opening the writer
   * @since 15.0 (in 14.0 with return type {@link BufferedWriter})
   */
  public Writer openBufferedStream() throws IOException {
    Writer writer = openStream();
    return (writer instanceof BufferedWriter)
        ? (BufferedWriter) writer
        : new BufferedWriter(writer);
  }

  /**

  @Override
  protected void setUp() throws Exception {
    sink = new TestByteSink();
  }

  public void testOpenBufferedStream() throws IOException {
    OutputStream out = sink.openBufferedStream();
    assertTrue(sink.wasStreamOpened());
    assertFalse(sink.wasStreamClosed());

    out.write(new byte[] {1, 2, 3, 4});
    out.close();

    assertTrue(sink.wasStreamClosed());

    } finally {
      out.close();
    }

    assertContainsExpectedBytes();
  }

  public void testOpenBufferedStream() throws IOException {
    OutputStream out = sink.openBufferedStream();
    try {
      ByteStreams.copy(new ByteArrayInputStream(data), out);
    } finally {
      out.close();
    }

    assertContainsExpectedBytes();
  }

  private TestCharSink sink;

  @Override
  public void setUp() {
    sink = new TestCharSink();
  }

  public void testOpenBufferedStream() throws IOException {
    Writer writer = sink.openBufferedStream();
    assertTrue(sink.wasStreamOpened());
    assertFalse(sink.wasStreamClosed());

    writer.write(STRING);
    writer.close();

    assertTrue(sink.wasStreamClosed());

      writer.write(data);
    } finally {
      writer.close();
    }

    assertContainsExpectedString();
  }

  public void testOpenBufferedStream() throws IOException {
    Writer writer = sink.openBufferedStream();
    try {
      writer.write(data);
    } finally {
      writer.close();
    }

    assertContainsExpectedString();
  }

  public void testWrite() throws IOException {
    sink.write(data);

  private TestCharSink sink;

  @Override
  public void setUp() {
    sink = new TestCharSink();
  }

  public void testOpenBufferedStream() throws IOException {
    Writer writer = sink.openBufferedStream();
    assertTrue(sink.wasStreamOpened());
    assertFalse(sink.wasStreamClosed());

    writer.write(STRING);
    writer.close();

    assertTrue(sink.wasStreamClosed());

    public InputStream openStream() throws IOException {
      return sliceStream(ByteSource.this.openStream());
    }

    @Override
    public InputStream openBufferedStream() throws IOException {
      return sliceStream(ByteSource.this.openBufferedStream());
    }

    private InputStream sliceStream(InputStream in) throws IOException {
      if (offset > 0) {
        long skipped;
        try {

      assertExpectedBytes(readBytes);
    } finally {
      in.close();
    }
  }

  public void testOpenBufferedStream() throws IOException {
    InputStream in = source.openBufferedStream();
    try {
      byte[] readBytes = ByteStreams.toByteArray(in);
      assertExpectedBytes(readBytes);
    } finally {
      in.close();
    }
  }

  @Override
  protected void setUp() throws Exception {
    sink = new TestByteSink();
  }

  public void testOpenBufferedStream() throws IOException {
    OutputStream out = sink.openBufferedStream();
    assertTrue(sink.wasStreamOpened());
    assertFalse(sink.wasStreamClosed());

    out.write(new byte[] {1, 2, 3, 4});
    out.close();

    assertTrue(sink.wasStreamClosed());

    } finally {
      out.close();
    }

    assertContainsExpectedBytes();
  }

  public void testOpenBufferedStream() throws IOException {
    OutputStream out = sink.openBufferedStream();
    try {
      ByteStreams.copy(new ByteArrayInputStream(data), out);
    } finally {
      out.close();
    }

    assertContainsExpectedBytes();
  }