BuiltSet<E>.build  constructor 
      
      BuiltSet<E>.build (
    
- dynamic updates(
- SetBuilder<
E>  
 - SetBuilder<
 
Creates a SetBuilder, applies updates to it, and builds.
Implementation
factory BuiltSet.build(Function(SetBuilder<E>) updates) =>
    (SetBuilder<E>()..update(updates)).build();