Closer is a convenience function that addresses the use-case of wanting to defer a Close() method that returns an error By using this function you can pass it the error the function returned as the second argument, if both the closer and the function error are not-nil the function error will get wrapped by the closer error, albeit with a new error struct, so the types and parent structure of the closer error would be lost if you use this function.

Returns path of currently running Go file.