support MultiChildRenderObjectElement feature

[Beyond-Chao]

There is any way to support MultiChildRenderObjectElement ? that will more flexibility and generality，thx

[OpenSphereSoftware]

Currently we wanted to integrate nil in our project. Since it is not supported for Lists we can only remove a small amount of our SizedBox()/Container() widgets. I think making this possible would lead to a very useful package to increase performance.

[Abhishek01039]

hello @Beyond-Chao

you can use the if condition inside a column, row, or listview with an else statement. so we actually have no need for a nil widget there.

[bgoncharuck]

@Abhishek01039 you can't. if you use any Builder inside MultiChildRenderObjectElement which can return nothing.