Given a module which has been previously loaded and is assigned to an alias
mod, unload(mod unloads it; reload(mod) unloads and
reloads it from its source.
box::unload(mod)box::reload(mod)
a module object to be unloaded or reloaded
box::unload and box::reload are called for their
side effect. They do not return anything.
Unloading a module causes it to be purged from the internal cache such that
the next subsequent box::use declaration will reload the module from
its source. box::reload unloads and reloads the specified modules and
all its transitive module dependencies. box::reload is not
merely a shortcut for calling box::unload followed by box::use,
because box::unload only unloads the specified module itself, not any
dependent modules.