unity3d arcamera 自动对焦功能实现 vuforia 启动是无法实行对焦，直接在arcamera相机上挂上此代码即可。(Realization of auto focus function of unity3d arcamera Vuforia startup is impossible to focus, and you can directly hang the code on the arcamera camera.)

Vuforia对焦，调用Vuforia对焦方法，实现自动对焦效果(Vuforia focuses and calls the Vuforia focusing method to achieve auto focusing effect.)