Useful if you don't know the type of an object and you want to ensure you don't bypass Unity's native-side null checks.

UnityNullCheck.cs

public static bool IsNull<T>(this T obj) where T : class
{
    if(obj is UnityEngine.Object unityObj)
    {
        /* Invokes Unity's custom == check for nulls.
         * This case technically only works because obj is
         * a "fake null" on the C# side by this point.
         * If its a true null it'd hit the else case instead,
         * which fortunately still returns what we want.
         */
        return unityObj == null;
    }
    else
    {
        // Uses regular C# null check
        return obj == null;
    }
}