ResourceManager for Single Assembly (Including localization resources) (for use with ILRepack or ILMerge)

SingleAssemblyResourceManager.cs

public class SingleAssemblyResourceManager : ResourceManager
{
    private readonly Type _resourceSource;
    private CultureInfo _neutralResourcesCulture;
    private readonly Dictionary<string, ResourceSet> _resourceSets;
    private readonly string[] _resourceNames;

    private SingleAssemblyResourceManager(Type resourceSource) :
        base(resourceSource)
    {
        _resourceSource = resourceSource;
        _resourceSets = new Dictionary<string, ResourceSet>(StringComparer.OrdinalIgnoreCase);
        _resourceNames = MainAssembly.GetManifestResourceNames();
    }

    protected override ResourceSet InternalGetResourceSet(CultureInfo culture, bool createIfNotExists,
        bool tryParents)
    {
        ResourceSet rs;
        if (_resourceSets.TryGetValue(culture.Name, out rs))
            return rs;

        if (_neutralResourcesCulture == null)
            _neutralResourcesCulture = GetNeutralResourcesLanguage(MainAssembly);

        if (culture.Equals(_neutralResourcesCulture))
            culture = CultureInfo.InvariantCulture;
        Stream store = GetManifestResourceStream(culture);
        rs = store != null
            ? new ResourceSet(store)
            : base.InternalGetResourceSet(culture, createIfNotExists, tryParents);
        _resourceSets.Add(culture.Name, rs);
        return rs;
    }

    public static void Initialize(Type resourceSource)
    {
        var rm = new SingleAssemblyResourceManager(resourceSource);
        FieldInfo mi = resourceSource.GetField("resourceMan",
            BindingFlags.Static | BindingFlags.NonPublic);
        mi?.SetValue(null, rm);
    }

    private Stream GetManifestResourceStream(CultureInfo culture)
    {
        string fileName = GetResourceFileName(culture);
        string fullName = string.Join(".", _resourceSource.FullName, fileName.Substring(fileName.IndexOf('.') + 1));
        fullName = _resourceNames.FirstOrDefault(n => n.Equals(fullName, StringComparison.OrdinalIgnoreCase));
        fileName = fullName?.Substring(fullName.Length - fileName.Length);
        return MainAssembly.GetManifestResourceStream(_resourceSource, fileName);
    }
}