Scroll to bottom with cdk-virtual-scroll (Angular 8)

Goal

Display a list of messages and scroll to bottom when a new message is received, even when I am at top. I would like to scroll fully bottom even with elements of different heights.

Problem

With virtual scroll I have to set the [itemSize] property, but for me it is not a static value:

• When a message is too long for one line it breaks in multiple, so its height changes.
• I have different types of messages with different heights (system messages for example).

Also, I am using ng-content to insert a button from the parent to load previous messages. What I see is that, when _scrollToBottom is invoked, instead of taking me to the bottom, it takes me to a bit higher. I suspect this is because of the different heights of elements inside virtual-scroll.

I have read this autosize scroll strategy issue from Angular: https://github.com/angular/components/issues/10113; but I am not sure this will solve my problem.

Any idea of what I could do will be welcome.

Test

Codesandbox: https://codesandbox.io/s/angular-virtual-scroll-biwn6

• When messages are loaded, scroll up.
• Send message. (When the new message is loaded, instead of scrolling to bottom, the virtual-scroll stops a little higher)
• Repeat

Video with the error: https://gofile.io/d/8NG9HD

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