tzdb_initialize() is intended to be called from a client package's
tzdb::tzdb_initialize() to ensure that the tzdb package
has been loaded.
The function itself doesn't do anything. It is instead called for the side-effect of loading the tzdb package. This does two things:
.onLoad() hook is run, which sets the path to the time zone
The callables in tzdb are registered, which allows them to be called from other packages.
There are alternative ways to ensure that tzdb is loaded. A client package
can alternatively import a function from tzdb into its package with the
@importFrom tag, or can call
requireNamespace("tzdb", quiet = TRUE) from