$ git clone -n https://src.fedoraproject.org/rpms/rust-tokio.git /var/lib/mock/f40-build-1967981-25215/root/chroot_tmpdir/scmroot/rust-tokio
Cloning into '/var/lib/mock/f40-build-1967981-25215/root/chroot_tmpdir/scmroot/rust-tokio'...
$ git fetch origin f28d7b583e9adf29233df4a0798d2200bef77b2a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-tokio
 * [new ref]         f28d7b583e9adf29233df4a0798d2200bef77b2a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f28d7b5 Update to version 1.39.2; Fixes RHBZ#2298245