plackup -L Shotgun
DESCRIPTIONShotgun loader delays the compilation and execution of your application until the runtime. When a new request comes in, this forks a new child, compiles your code and runs the application.
This should be an ultimate alternative solution when reloading with Plack::Middleware::Refresh doesn't work, or plackup's default "-r" filesystem watcher causes problems. I can imagine this is useful for applications which expects their application is only evaluated once (like in-file templates) or on operating systems with broken fork implementation, etc.
This is much like good old CGI's fork and run but you don't need a web server, and there's a benefit of preloading modules that are not likely to change. For instance if you develop a web application using Moose and DBIx::Class,
plackup -MMoose -MDBIx::Class -L Shotgun yourapp.psgi
would preload those modules and only re-evaluates your code in every request.