[WebRoot] uses these to preprocess requests. They can do various tasks ranging from setting up session variables, querying data from a database, collect usage information, or to block a non admin user from accessing an admin only section of the site (Note that [WebPermission]s are better suited for this purpose though.)
When a request is received [WebRoot] (if it's used for a particular server) will go through all of it's registered Middlewares in order, and call their on_before_handle_request_main() method. If it returns true that means the middleware ended up handling that request, which means the request should not be processed further. This usually means that the Middleware sent an error.
This method is used to process the given [WebServerRequest]. Return false if you want the processing to continue, return true to signal to the caller [WebRoot] that this [WebServerRequest] handled the request, and no further processing should be done. If you do this, you need to actually send something back in your implementation using the [WebServerRequest], othrewise the [WebServerRequest] will just get kept alive hanging until a timeout occurs.
