Time::Piece regional timezone configuration via TZ environment variable

Perl's core Time::Piece and Time::Local modules rely on the underlying system C library for timezone offsets. When managing regional time conversions, the TZ environment variable is typically used to define the process-level timezone context for localtime() calls.

A design challenge arises when a single process must handle multiple regional time zones dynamically without restarting the interpreter or relying on external non-core modules like DateTime. Because the TZ variable affects the entire process, switching zones for specific date conversions can create race conditions in multi-threaded environments or inconsistent state in long-running scripts.

• Is there a documented method within Time::Piece to specify a timezone offset per object instance rather than globally?
• How does Time::Local::timelocal behave when the TZ variable is modified mid-execution across different operating systems?