It would be great if Akonadi/DAV would support preemptive authentication, as that will speed up syncs with the WebDAV server. RFC 2617 Section 2: A client MAY preemptively send the corresponding Authorization header with requests for resources in that space without receipt of another challenge from the server. Several other WebDAV clients (e.g. Android CardDAV-Sync, CalDAV-Sync, DAVdroid) and Apache's HTTP client library support this.
It would be great if this issue could be addressed as the log file of my owncloud installation is full of messages regarding missing authentication headers.
Looks more like a job for KIO http module. I can't find an option to enable this.