Configurable

Magic getter

Will return $this->foo if it exists, then $this->getFoo() or will throw an exception if neither exists

Magic setter

Will call $this->setFoo($propValue) if it exists, otherwise it will set $this->foo. If $this->foo is a NormalizedCollection, we do not replace it, instead we clear() it then fill it back up. It will not overwrite an object with a different incompatible object (of a different, non-extending class) and it will throw an exception if the PHP type cannot match without incurring data loss.

Test whether a property is set

Unset a property, if the class supports it