code: public void putDuration(int duration) throws JSONException {
          if (duration > 0) {
              this.duration = duration;
              this.put(Defines.LinkParam.Duration.getKey(), duration);
          }
      }
docs: <p>[Optional] You can set the duration manually. This is the time that
  Branch allows a click to remain outstanding and be eligible to be matched
  with a new app session.</p>
  
  @param duration An {@link Integer} value in seconds.
  @throws JSONException The parameter value must be in valid JSON format, or a
  {@link JSONException} will be thrown.