As I can see, this split was done in a manner that opendal processes URL prefixes (out of the current issue scope).

But this concept is not useful, IMO.

I prefer to pass a single SCCACHE_WEBDAV_ENDPOINT and extract SCCACHE_WEBDAV_KEY_PREFIX from the endpoint. If opendal needs, SCCACHE_WEBDAV_ENDPOINT value may be removed from SCCACHE_WEBDAV_KEY_PREFIX too (for better understanding/support via opendal provider).

If both SCCACHE_WEBDAV_ENDPOINT path is non-root and SCCACHE_WEBDAV_ENDPOINT is not empty, we should:

1. Pass them without any changes to the opendal
2. Check via an assert! and finish the program as an invalid case

I prefer to use the second variant, but maybe some implementations exist that requires both of the values (I don't know anything about them).