variable to layout

I am facing the similar issue, and unfortunately there is no documentation regarding the issue (should be in view-layout related section in the documentation) which I presume there is no feature about it in the current version of CI. I ended up utilizing the layout as simple as possible with very little needs of logic, and utilizing other view's features, like loading multiple views, cell, etc. Flexible, but less structured. Lets hope CI team adds the feature in the future.
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EDIT:
I think made a mistake by assuming that there is no feature about it because there is no documentation about it. It seems we don't need to pass any data to the layout since it can detect all data passed from controller to view.