this derivation will be built:
  /nix/store/vmq9zl0lpld5xgg3r0318wpffq1sf8yp-check-agent-slack.drv
building '/nix/store/vmq9zl0lpld5xgg3r0318wpffq1sf8yp-check-agent-slack.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=22&system=aarch64-linux'
building '/nix/store/vmq9zl0lpld5xgg3r0318wpffq1sf8yp-check-agent-slack.drv' on farm.numtide.com:50051
check-agent-slack> bld3: building vmq9zl0lpld5xgg3r0318wpffq1sf8yp-check-agent-slack.drv

upload niks3: ok