these 4 derivations will be built:
  /nix/store/40bi38222q1k2jwv86bx3qi1ya4n5nb8-cargo-nix-plugin-mirror-test-env-var.drv
  /nix/store/sfa86apl90dbchzm3l2xv3kq3n2ggfyc-cargo-nix-plugin-mirror-test-cargo-config.drv
  /nix/store/v1bs7i11a9agabk8ghx8r1v5af5g8a6g-cargo-nix-plugin-mirror-test-https-custom-ca.drv
  /nix/store/qm561jxdwn2yj8vhk72x8a42y1iavrk5-cargo-nix-plugin-mirror-tests.drv
building '/nix/store/sfa86apl90dbchzm3l2xv3kq3n2ggfyc-cargo-nix-plugin-mirror-test-cargo-config.drv' on 'ssh-ng://nix@jamie'
building '/nix/store/40bi38222q1k2jwv86bx3qi1ya4n5nb8-cargo-nix-plugin-mirror-test-env-var.drv' on 'ssh-ng://nix@jamie'
building '/nix/store/v1bs7i11a9agabk8ghx8r1v5af5g8a6g-cargo-nix-plugin-mirror-test-https-custom-ca.drv' on 'ssh-ng://nix@jamie'