$ git clone -n https://src.fedoraproject.org/rpms/rust-tokio.git /var/lib/mock/f40-build-2653368-66900/root/chroot_tmpdir/scmroot/rust-tokio
Cloning into '/var/lib/mock/f40-build-2653368-66900/root/chroot_tmpdir/scmroot/rust-tokio'...
$ git fetch origin 18297ad5c0bf71019e4209c6ac0a8201ae28922e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-tokio
 * [new ref]         18297ad5c0bf71019e4209c6ac0a8201ae28922e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 18297ad Update to version 1.36.0; Fixes RHBZ#2262394