code: @Override
      public void write(int oneChar) throws IOException {
          synchronized (lock) {
              checkStatus();
              CharBuffer chars = CharBuffer.wrap(new char[] { (char) oneChar });
              convert(chars);
          }
      }
docs: Writes the character {@code oneChar} to this writer. The lowest two bytes
  of the integer {@code oneChar} are immediately converted to bytes by the
  character converter and stored in a local buffer. If the buffer gets full
  by converting this character, this writer is flushed.
  
  @param oneChar
  the character to write.
  @throws IOException
  if this writer is closed or another I/O error occurs.