Hello,

I found a bug where if a StreamBuilder is the first child of a CustomScrollView it will throw these two errors randomly.

flutter: Another exception was thrown: 'package:flutter/src/rendering/viewport.dart': Failed assertion: line 1213 pos 12: 'center.parent == this': is not true.
flutter: Another exception was thrown: NoSuchMethodError: The getter 'visible' was called on null.

It does not matter if the StreamBuilder is returning a sliver or not.

What's worse is it's not consistent. Out of 10 tries it will happen maybe 6 times and in seemingly random order. Possible race condition?

The workaround is to place a SliverToBoxAdapter() as the first child, then the problem goes away.