Rebase and forward requests which path match the provided basepath.
If the VSGI.Request.uri path has the provided prefix, it is stripped and the resulting request is forwared.
Typically, a leading slash and no ending slash are used to form the prefix path (e.g. '/user').
If 'next' is called while forwarding, the URI path is restored.
Error which message consist of a 'Location' header are prefixed by the basepath.
| path |
path prefix stripped on forwarded requests |
| forward |
callback used to forward the request |