docs: public void writeThrowable(OutputStream out, Throwable value) throws IOException {
          writeStartObject(out);
          writeSerializedField(out, OM_THROWABLE, value);
          StringWriter sw = new StringWriter();
          value.printStackTrace(new PrintWriter(sw));
          writeStringField(out, OM_STACKTRACE, sw.toString());
          writeEndObject(out);
      }