// optimize for common output types which are optimized to deal with char[]
      if (to instanceof StringBuilder) {
        return copyReaderToBuilder((Reader) from, (StringBuilder) to);
      } else {
        return copyReaderToWriter((Reader) from, asWriter(to));
      }
    }

    checkNotNull(from);
    checkNotNull(to);
    long total = 0;
    CharBuffer buf = createBuffer();
    while (from.read(buf) != -1) {