[pbs-devel] [PATCH proxmox-backup] fix #3359: fix blocking writes in async code during pxar create

[Dietmar Maurer]

> Fixes: 6afb60abf557 ("asyncify pxar create_archive")

I am not sure, but maybe 6afb60abf557 is also the cause for 
the performance regression?

(reported at https://bugzilla.proxmox.com/show_bug.cgi?id=3174)