code: public TouchActions flick(WebElement onElement, int xOffset, int yOffset, int speed) {
      if (touchScreen != null) {
        action.addAction(new FlickAction(touchScreen, (Locatable) onElement, xOffset, yOffset, speed));
      }
      return this;
    }
docs: Allows the execution of flick gestures starting in a location's element.
  
  @param onElement The {@link WebElement} to flick on
  @param xOffset   The x offset relative to the viewport
  @param yOffset   The y offset relative to the viewport
  @param speed speed to flick, 0 = normal, 1 = fast, 2 = slow
  @return self