When using a storage backend, e.g. S3, should we expect clients to experience connection speeds relative to that of S3 or relative to that of the seafile server? In other words, when a client interacts with stored data, is it routed through the server or connected directly to S3? When a client downloads a new library, will the download speed be the upload speed of S3 or of the seafile server? Does storage backend encryption affect this?