Issue with focus on ChattoViewController Start

Hi,
I am preloading my data in Another ViewController and on display of ChattoViewController my array is already ready.
When i open chats from starting are visible in the viewcontroller and i have to scroll down each time at bottom manually.
I call `self.delegate?.chatDataSourceDidUpdate(self, updateType: .normal)` at the end of preload.
If I try to change focus in ViewDidAppear the scroll to bottom is visible keeping animation flag to false also.

Start with ChattoViewController's viewDidAppear behavior and the chatDataSourceDidUpdate(self, updateType: .normal) call used after preloading. Reproduce the case where chats are already available when the controller opens, then check whether the initial view is at the bottom without a visible scroll animation; done means the latest messages are shown at the bottom on first display.

Written by the indexing model from the issue text.