public long copyTo(Appendable appendable) throws IOException {
    checkNotNull(appendable);

    Closer closer = Closer.create();
    try {
      Reader reader = closer.register(openStream());
      return CharStreams.copy(reader, appendable);
    } catch (Throwable e) {
      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**
   * Copies the contents of this source to the given sink.

   *     this sink
   */
  @CanIgnoreReturnValue
  public long writeFrom(Readable readable) throws IOException {
    checkNotNull(readable);

    try (Writer out = openStream()) {
      return CharStreams.copy(readable, out);
    }
  }