public PackageBuilder() { Files = new Collection<IPackageFile>(); DependencySets = new Collection<PackageDependencySet>(); FrameworkReferences = new Collection<FrameworkAssemblyReference>(); PackageAssemblyReferences = new Collection<PackageReferenceSet>(); Authors = new HashSet<string>(); Owners = new HashSet<string>(); Tags = new HashSet<string>(); }