If you are seeing this error, reason could be:

1) the ./staticlib/$os/$arch directory doesn't exist at compile time
2) network is disabled during cargo build, or env OFFLINE=1 is set
3) current os/arch is unsupported (see https://github.com/btwiuse/pub/releases/latest/)

In either case, please consider installing it via `go install` instead:

   go install github.com/btwiuse/pub/cmd/pub@latest