zsync -i precise-desktop-i386.iso http://releases.ubuntu.com/precise/ubuntu-12.04-desktop-i386.iso.zsync
#################### 100.0% 166.7 kBps DONE     

reading seed file precise-desktop-i386.iso: ****************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************Read precise-desktop-i386.iso. Target 81.6% complete.      
reading seed file ubuntu-12.04-desktop-i386.iso.part: **************************************************************************************************************************************************************************************************************************************************************************Read ubuntu-12.04-desktop-i386.iso.part. Target 81.6% complete.      
downloading from http://releases.ubuntu.com/precise/ubuntu-12.04-desktop-i386.iso:
################---- 81.6% 0.0 kBps aborted    

failed to retrieve from ubuntu-12.04-desktop-i386.iso
Aborting, download available in ubuntu-12.04-desktop-i386.iso.part
verifying download.
ubuntu@ubuntu:~/Downloads$