code: public void set(String key, Object value) {
      if (!StringUtil.isEmpty(key) && null != value) {
        pendingInstanceData.put(key, value);
      }
    }
docs: Add a key-value pair to this conversation
  @param key   Keys must be alphanumerical plus underscore, and start with a letter.
  @param value Values may be numerical, String, JSONObject, JSONArray, JSONObject.NULL, or other
  AVObjects. value may not be null.