this derivation will be built:
  /nix/store/7chfwndwsmib1x1dc127k2104d03kg12-check-workmux.drv
building '/nix/store/7chfwndwsmib1x1dc127k2104d03kg12-check-workmux.drv' on 'grpc://farm.numtide.com:50051?client-cert=/run/secrets/vars/per-machine/bld1/nix-farm-ci/crt&client-key=/run/secrets/vars/per-machine/bld1/nix-farm-ci/key&connect-timeout=20&system=aarch64-linux'
building '/nix/store/7chfwndwsmib1x1dc127k2104d03kg12-check-workmux.drv' on farm.numtide.com:50051
check-workmux> bld4: building 7chfwndwsmib1x1dc127k2104d03kg12-check-workmux.drv

upload niks3: ok