Demo app crashes when trying to switch camera front facing camera

[JoeyZh]

here is the log:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.google.android.cameraview.demo, PID: 5552
java.lang.RuntimeException: Camera is being used after Camera.release() was called
at android.hardware.Camera.native_getParameters(Native Method)
at android.hardware.Camera.getParameters(Camera.java:3337)
at android.hardware.Camera.cameraInitVersion(Camera.java:770)
at android.hardware.Camera.cameraInitNormal(Camera.java:784)
at android.hardware.Camera.(Camera.java:807)
at android.hardware.Camera.open(Camera.java:506)
at com.google.android.cameraview.Camera1.openCamera(Camera1.java:276)
at com.google.android.cameraview.Camera1.start(Camera1.java:89)
at com.google.android.cameraview.Camera1.setFacing(Camera1.java:134)
at com.google.android.cameraview.CameraView.setFacing(CameraView.java:317)
at com.google.android.cameraview.demo.MainActivity.onOptionsItemSelected(MainActivity.java:212)
at android.app.Activity.onMenuItemSelected(Activity.java:2940)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:361)
at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:195)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:108)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:108)
at android.support.v7.app.ToolbarActionBar$2.onMenuItemClick(ToolbarActionBar.java:65)
at android.support.v7.widget.Toolbar$1.onMenuItemClick(Toolbar.java:202)
at android.support.v7.widget.ActionMenuView$MenuBuilderCallback.onMenuItemSelected(ActionMenuView.java:780)
at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:822)
at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:171)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:973)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:963)
at android.support.v7.widget.ActionMenuView.invokeItem(ActionMenuView.java:624)
at android.support.v7.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:150)
at android.view.View.performClick(View.java:4848)
at android.view.View$PerformClick.run(View.java:20255)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5643)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)