FdSource & from, FdSink & to, const PathSet & paths, counter & bytesReceived)

    FdSource & from, FdSink & to, const PathSet & paths, counter & bytesReceived,
    std::shared_ptr<FSAccessor> accessor)

    destStore->importPaths(false, from);

    destStore->importPaths(false, from, accessor);

        result.accessor = destStore->getFSAccessor();

        copyClosureFrom(destStore, from, to, outputs, bytesReceived);

        copyClosureFrom(destStore, from, to, outputs, bytesReceived, result.accessor);

        if (result.success()) res = getBuildOutput(destStore, destStore->getFSAccessor(), step->drv);

        if (result.success())
            res = getBuildOutput(destStore, ref<FSAccessor>(result.accessor), step->drv);

    std::shared_ptr<nix::FSAccessor> accessor;