Unable to access LogicalPlanBuilder.plan inside a new trail implementation

[emgeee]

Is your feature request related to a problem or challenge?

We're looking to extend the LogicalPlanBuilder via a trait, however we need to be able to access LogicalPlanBuilder.plan which is currently private.

Describe the solution you'd like

Either make LogicalPlanBuilder.plan public or add a public getter method that returns a reference to the LogicalPlan

Describe alternatives you've considered

No response

Additional context

Either solution will work for our current needs but I do not whether the preference is to make internal variables public or add getter methods.