Whenever a shot is fired, or the weapon is reloaded, this hook is called to give subclasses an
opportunity to save the changed value, usually as the item's health value.
“Op Ed” does not stand for “Opinions of the Editor,” but instead,
“Operator Editable…” It's just going to be typed so often that the
malapropistic abbreviation seemed entirely appropriate.
The order's source code is an identifier which maps to the
payment gateway class, but is user-visible as a part of the total
payment identifier (source, code, and sequence number)