Returns disk usage as a fraction between 0 and 1 for the given mount point.
Uses GIO's query_filesystem_info for a portable implementation.
query_filesystem_info
Mount point path (defaults to '/')
'/'
Disk usage ratio (0–1), or -1 if unavailable
Returns disk usage as a fraction between 0 and 1 for the given mount point.
Uses GIO's
query_filesystem_infofor a portable implementation.