$ git clone -n https://src.fedoraproject.org/rpms/rust-io-extras.git /var/lib/mock/f45-build-42617-795/root/chroot_tmpdir/scmroot/rust-io-extras
Cloning into '/var/lib/mock/f45-build-42617-795/root/chroot_tmpdir/scmroot/rust-io-extras'...
$ git fetch origin 3670faf6b6b1eec54e804ee22e5ab95febd1f2bf:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-io-extras
 * [new ref]         3670faf6b6b1eec54e804ee22e5ab95febd1f2bf -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3670faf Update to version 0.19.0; Fixes RHBZ#2386913