在android中计算相机的焦距需要一些时间，所以发布这篇文章可以帮助其他人。
CameraManagerCompat.from(this(.unwrap((.getCameraCharacteristics("0"(.get(CameraCharacteristics.LENS_INFO_AVAILABLE_OCAL_LENGTHS(
CameraManagerCompat.from(this(.unwrap((.getCameraCharacteristics("0"(.get(CameraCharacteristics.LENS_INFO_AVAILABLE_OCAL_LENGTHS(
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