To hit QueryAllValidPaths: nix-store --dump-db
To hit OptimiseStore: nix-store --optimise
To hit QuerySubstitutablePaths: nix-env --install --prebuilt-only
To hit QueryValidDerivers: nix derivation show (on the output path of a derivation)
To hit RegisterDrvOutput: make a ca-derivation, and copy all of its
outputs, like nix copy '/nix/store/h2cz7vw504fx24qc6pzz8cmlin2cfzkp-hello.drv^*' --to 'ssh-ng://zeus?remote-program=/home/jneeman/tweag/nix-remote-rust/nix-remote-rust.sh'
To hit AddSignatures, build (locally, with --no-build-substituters) a derivation, and then nix store copy-sigs from a substituter
To hit QueryRealisation, nix realisation info on a CA derivation
To hit AddBuildLog, nix store copy-log
To hit QueryReferrers, nix-store --query --referrers
To hit BuildDerivation, see the remote-build.sh script.