Unkown filesize - rclone cache/tmp issues with very large files?

What is the problem you are having with rclone?

I want to download a large file (100 GB) directly to the mounted webdav storage, without caching and without saving to /tmp/, because the file is too big for the server's internal storage capacity. Unfortunately when downloading the file, the filesize is unkown, so wget just keeps downloading until its finished.

I think the unkown filesize causes issues with rclone's cache and tmp.
rclone keeps filling /tmp/ with data. Eventually it crashes, as the server's internal storage is full.

Server Internal Storage: 20 GB
external WebDav Storage (/mnt/webdav): 5 TB
File-Size: 100 GB

What is your rclone version (output from rclone version)

rclone v1.56.0 (latest)

Which OS you are using and how many bits (eg Windows 7, 64 bit)

Ubuntu 20.04 64bit

Which cloud storage system are you using? (eg Google Drive)

WebDAV Server

The command you were trying to run (eg rclone copy /tmp remote:tmp)

rclone mount --buffer-size 64M --vfs-read-chunk-size 128M --vfs-read-chunk-size-limit 128M webdav:/data /mnt/webdav --allow-other --cache-tmp-upload-path /mnt/webdav
cd /mnt/webdav
# download file.zip with unkown filesize. Linking directly to file.zip does not work.
wget "https://www.domain.com/path/to/file"