guava/src/com/google/common/io/CharSink.java
public void writeLines(Iterable<? extends CharSequence> lines, String lineSeparator)
      throws IOException {
    writeLines(lines.iterator(), lineSeparator);
  }
public void writeLines(Iterable<? extends CharSequence> lines, String lineSeparator)
      throws IOException {
    writeLines(lines.iterator(), lineSeparator);
  }
Writes the given lines of text to this sink with each line (including the last) terminated with
the given line separator.

@throws IOException if an I/O error occurs while writing to this sink