namespace System.Runtime.InteropServices.Marshalling
{
    [CLSCompliant(false)]
    [ContiguousCollectionMarshaller]
    [CustomMarshaller(typeof(Span<?>), MarshalMode.Default, typeof(SpanMarshaller<?, ?>))]
    [CustomMarshaller(typeof(Span<?>), MarshalMode.ManagedToUnmanagedIn, typeof(ManagedToUnmanagedIn))]
    public static class SpanMarshaller<T, TUnmanagedElement>
        where TUnmanagedElement, unmanaged, struct
    {
        public static TUnmanagedElement* AllocateContainerForUnmanagedElements(Span<T> managed, out int numElements);
    }
}