See Mail::Box::Locker
See SYNOPSIS in Mail::Box::Locker
The ::Flock
object locks the folder by creating an exclusive lock on
the file using the kernel's flock
facilities. This lock is created
on a separate file-handle to the folder file, so not the handle which
is reading.
File locking does not work in some situations, for instance for
operating systems do not support flock
.
See DESCRIPTION in Mail::Box::Locker