We'll use lower-level Socket and avoid IO::Socket::UNIX,
use Cwd::fastcwd(*), avoid IO::Handle->autoflush by
using the select operator, and reuse buffer for reading
the socket while avoiding unnecessary $/ localization
in a tiny script.
All these things adds up to ~5-10 ms savings on my loaded
system.
(*) caveats about fastcwd won't apply since lei won't work
in removed directories.