I'm updating/rewriting a C# program from .net 4.8 to .net 8, but the code uses a lot of Func .BeginInvoke() and .EndInvoke() calls, which no longer appear to be supported.

Question: What are some alternatives to Func - BeginInvoke(), assuming this cannot be fixed?

The exception caught:

System.PlatformNotSupportedException: 'Operation is not supported on this platform.'

Source: System.Private.CoreLib

StackTrace: at System.Func`1.BeginInvoke(AsyncCallback callback, Object object)...

Code example:

private static readonly Func> QueryUnprocessed =
    (ctx) => from p in ctx.PAs
             where !p.FaxOutTime.HasValue
                && !p.Duplicate
                && !p.IsLetter
                && !p.No_Process
                && !p.pa_type.Equals("D")
             select p;

public static void GetUnprocessed(Action> callback)
{
    Func> load = () =>
    {
        try
        {
            using (var ctx = PaEntities.NewContext())
            {
                var unprocessedPAs = QueryUnprocessed(ctx).ToList();

                return unprocessedPAs.ToList();
            }
        }
        catch (Exception e)
        {
            // TODO: Log error
            return null;
        }
    };

    // Error kicks off at BeginInvoke
    load.BeginInvoke((ar) => callback(load.EndInvoke(ar)), null);
}