Why?

cache.cs

// OK

internal static class Cache
{
    private static readonly ResourceCache _cache;

    static Cache()
    {
        _cache = AtomicNET.GetSubsystem<ResourceCache>();
    }

    public static T Get<T>(string path) where T : Resource
    {
        return _cache.Get<T>(path);
    }
}

// NOT OK?

internal static class Cache
{
    private static readonly ResourceCache _cache = AtomicNET.GetSubsystem<ResourceCache>();

    public static T Get<T>(string path) where T : Resource
    {
        return _cache.Get<T>(path);
    }
}