Calling InstallPackageAsync with my custom FolderNuGetProject does not install files

I writing an app which has plugins downloadable from nuget, which can then be dynamically loaded into my application - similair to this interesting talk.

I derive my class from the NuGet.ProjectManagement.FolderNuGetProject, however files are not installed after calling NuGetPackageManager.InstallPackageAsync with my custom folder project, only packages.config is updated per below:

<?xml version="1.0" encoding="utf-8"?><packages><package id="Unified.Mqtt.Pattern" version="1.0.3" targetFramework="netstandard2.0" /></packages>

But no files in the directory other than that:

PS C:\ProgramData\unified.msp> dir    Directory: C:\ProgramData\unified.mspMode                 LastWriteTime         Length Name----                 -------------         ------ -----a----        07/08/2022     11:07            156 packages.config

The Project class is below:

public class PluginProject : FolderNuGetProject{    private readonly PackagesConfigNuGetProject packagesConfigProject;    public PluginProject(string root) : base(root)    {        this.packagesConfigProject = new PackagesConfigNuGetProject(root, new Dictionary<string, object>()        {            { "TargetFramework", NuGetFramework.AnyFramework },            { "Name", "My.Package.Installer" }        });    }    public override Task<IEnumerable<PackageReference>> GetInstalledPackagesAsync(CancellationToken cancellationToken)    {        return this.packagesConfigProject.GetInstalledPackagesAsync(cancellationToken);    }    public override Task<bool> InstallPackageAsync(PackageIdentity packageIdentity, DownloadResourceResult downloadResourceResult,        INuGetProjectContext nuGetProjectContext, CancellationToken token)    {        return this.packagesConfigProject            .InstallPackageAsync(packageIdentity, downloadResourceResult, nuGetProjectContext, token);    }}

And the overall plugin manager is below (which scaffolds everything together into the NuGetPackangeManager method calls. It does list installed packages, and can install (ableit without the actual file contents):

public class NugetPluginManager{    private readonly IOptions<NugetPluginManagerSettings> settings;    private readonly LoggerAdapter logger;    public NugetPluginManager(IOptions<NugetPluginManagerSettings> settings, ILogger<NugetPluginManager> logger)    {        this.settings = settings;        this.logger = new LoggerAdapter(logger);    }    private static (SourceRepository Repository, List<Lazy<INuGetResourceProvider>> Providers) GetRepository(string repositoryUrl)    {        var providers = new List<Lazy<INuGetResourceProvider>>();        providers.AddRange(Repository.Provider.GetCoreV3());        var packageSource = new PackageSource(repositoryUrl);        var repository = new SourceRepository(packageSource, providers);        if(packageSource.SourceUri.Scheme != Uri.UriSchemeHttps)            throw new ArgumentException($"{repositoryUrl} is not https.", nameof(repositoryUrl));        return (repository, providers);    }    public async Task<IEnumerable<PackageReference>> GetInstalledPackages(CancellationToken cancellationToken = default)    {        var commonApplicationDataPath = Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData);        var rootAppPath = Path.Combine(commonApplicationDataPath, "unified.msp");        var packagesPath = Path.Combine(rootAppPath, "packages");        var project = new PluginProject(rootAppPath);        return await project.GetInstalledPackagesAsync(cancellationToken);    }    public async Task Install(string repositoryUrl, string packageName, string version, bool includeDependencies,        bool includePreRelease, CancellationToken cancellationToken = default)    {        var (repository, providers) = GetRepository(repositoryUrl);        var commonApplicationDataPath = Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData);        var rootAppPath = Path.Combine(commonApplicationDataPath, "unified.msp");        var packagesPath = Path.Combine(rootAppPath, "packages");        var project = new PluginProject(rootAppPath);        var defaultSettings = Settings.LoadDefaultSettings(rootAppPath, null, new XPlatMachineWideSetting());        // Create the package manager - TODO: https://github.com/NuGet/Home/issues/8479        #pragma warning disable CS0618 // Type or member is obsolete        var repositoryProvider = new SourceRepositoryProvider(defaultSettings, providers);        #pragma warning restore CS0618 // Type or member is obsolete        var packageManager = new NuGetPackageManager(repositoryProvider, defaultSettings, packagesPath)        {            PackagesFolderNuGetProject = project        };        var dependencyBehaviour = includeDependencies ? DependencyBehavior.Lowest : DependencyBehavior.Ignore;        var resolutionContext =            new ResolutionContext(dependencyBehaviour, includePreRelease, false, VersionConstraints.None);        var projectContext = new EmptyNuGetProjectContext();        await packageManager.InstallPackageAsync(                                packageManager.PackagesFolderNuGetProject,                                new PackageIdentity(packageName, NuGetVersion.Parse(version)),                                resolutionContext,                                projectContext,                                repository,                                Array.Empty<SourceRepository>(),                                cancellationToken);    }}