NOTE
Template Method Pattern
Fixing an algorithm skeleton while allowing selected steps to vary in subclasses or callbacks.
This is a historical learning note and may contain outdated or incomplete understanding.
Template Method defines a stable algorithm skeleton and delegates selected steps to overridable operations. It is useful when the high-level sequence is fixed but some policy varies.
Inheritance-based templates can couple subclasses tightly to lifecycle hooks. Modern designs often express the same idea with composition, callbacks, or strategy objects when that produces clearer dependencies.