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