List of best mirrors for IP address 18.116.74.199, located in an unknown country.
I am very sorry, but no mirror was found. Feel free to download directly:
http://mirrordirector-mb.raspbian.org/raspbian/pool/main/z/zchunk/libzck-dev_1.3.1+ds1-1+rpi1+b1_armhf.deb