Why PassNode::write creates a new resource?

[BrodaJarek]

I am trying to understand why PassNode::Write() creates a new resource. I've read EA article and they say This allows us to catch errors when resources are modified in undefined order (when the same resource is written by different passes). Renaming resources enforce a specific execution order of the render passes.. The passes are executed in a loop, and I don't see any threading between them, so how can they be executed in undefined order?

[romainguy]

@pixelflinger was just explaining this to someone else yesterday :)

"It returns a new handle to the resource

This is to prevent you from making circles"