Android FotoApparat library how to make the cameraView zoom how?

Question

i am using the below library in my android application

 implementation 'io.fotoapparat:fotoapparat:2.7.0'

and this is the implementation of the fotoapparat instance build

  fotoapparat = Fotoapparat.with(this)
            .into(camera_view!!)
            .previewScaleType(ScaleType.CenterCrop)
            .lensPosition(back())
            .focusMode(
                firstAvailable(
                  
                    autoFocus()
                )
            ).flash(
                firstAvailable(
                    autoRedEye(),
                    autoFlash(),
                    torch()
                )
            ).build()

and the camera in xml is like

<io.fotoapparat.view.CameraView
    android:id="@+id/camera_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

i need to let the camera make zoom in and out how ?