[MethodImpl(MethodImplOptions.AggressiveInlining)]
public T Read<T>()
{
    if (TypeCache<T>.CanUsePadding16)
        return Unsafe.As<Padding16, T>(ref _valueStorage);

    return (T)_defaultStorage;
}

public static class TypeCache<T>
{
    public static readonly bool CanUsePadding16;

    static TypeCache()
    {
        CanUsePadding16 =
            !IsReferenceOrContainsReferences(typeof(T)) && Unsafe.SizeOf<T>() <= 16;
    }

    private static bool IsReferenceOrContainsReferences(Type type)
    {
        // Custom implementation using reflection
    }
}