TimezoneIANA attempts to determine the local timezone in IANA format.
If the TZ environment variable is set, this is used.
Otherwise, /etc/localtime is used to determine the timezone.
Reference: https://stackoverflow.com/a/63805394
On Windows platforms, instead of reading /etc/localtime, powershell
is used instead to get the current time location in IANA format.
Reference: https://superuser.com/a/1584968