code: public FormattedStringBuilder append(Throwable t) { 
          ByteArrayOutputStream os = new ByteArrayOutputStream();
          PrintStream p = new PrintStream(os);
          t.printStackTrace(p);
          p.close();
          return append(os.toString());
      }
docs: Appends the stack trace of the Throwable argument to this sequence.
  @param t Exception to print.
  @return The updated instance of FormattedStringBuilder.