Thanks for ur quick response Patrick.

Can i add the suspend /resume mechanism in an old version of syncevolution ? i mean the 0.8.1 version .

is there any method to add it safely ? 

It will help me to do some tests concerning slow sync. I wanna test the duplication on the server due to slow sync in order to identify the reasons and how to avoid it using suspend/resume .

if there is any other possible solution that can avoid slow sync in the 0.8.1 version ? .

I know that the new version implements this mechanism but the problem that i'm familiarized with this old version . until i succeed to add my sqlite backend to new syncevolution version  that use synthesis, i wanna test this mechanism on the old version . Please help me to do this . 

Best Regards.