reinforce library to re-load

Hi,

I am wondering if there is a parameter in library() so that it can
reinforce package to be reloaded. It helps when you test your modified
package by yourself. Otherwise, my way is to re-start Rgui.

(by reading ?library, I understand this option is not implemented)
"...Both functions check and update the list of currently loaded
packages and do not reload a package which is already loaded.
(Furthermore, if the package has a name space and a name space of that
name is already loaded, they work from the existing names space rather
than reloading from the file system.)"

Thanks.