code: void addPendingChange(String key, String value) {
          this.addPendingChange(key, JsonValue.valueOf(value));
      }
docs: Adds a pending field change that needs to be sent to the API. It will be included in the JSON string the next
  time {@link #getPendingChanges} is called.
  @param key   the name of the field.
  @param value the new String value of the field.