* the operating system's default line separator. This method is equivalent to {@code
   * writeLines(lines, System.getProperty("line.separator"))}.
   *
   * @throws IOException if an I/O error occurs while writing to this sink
   */
  public void writeLines(Iterable<? extends CharSequence> lines) throws IOException {
    writeLines(lines, System.getProperty("line.separator"));
  }

  /**

    assertFalse(in.closed());
  }

  public void testWriteLines_withSpecificSeparator() throws IOException {
    sink.writeLines(ImmutableList.of("foo", "bar", "baz"), "\n");
    assertEquals("foo\nbar\nbaz\n", sink.getString());
  }

  public void testWriteLines_withDefaultSeparator() throws IOException {
    sink.writeLines(ImmutableList.of("foo", "bar", "baz"));
    String separator = System.getProperty("line.separator");