$ git clone -n https://src.fedoraproject.org/rpms/rust-tokio.git /var/lib/mock/f40-build-703999-12986/root/chroot_tmpdir/scmroot/rust-tokio
Cloning into '/var/lib/mock/f40-build-703999-12986/root/chroot_tmpdir/scmroot/rust-tokio'...
$ git fetch origin dc0b8789fc6c61213a6fa25e08b544653c6d249f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-tokio
 * [new ref]         dc0b8789fc6c61213a6fa25e08b544653c6d249f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dc0b878 Update to version 1.37.0; Fixes RHBZ#2272079