A base single Instance CU would be work well. No need to recreate with extensions.The SI CU just needs to store KeyValue pairs to be used later in a process. Keep it simple.codeunit 55108 SingleInstanceKeyValues{  SingleInstance = true;   var    KeyValues: Dictionary of [Text, Text];  procedure SetKeyValue(KeyName: Text; KeyValue: Text)  begin    if KeyValues.ContainsKey(KeyName) then      KeyValues.Remove(KeyName);    KeyValues.Add(KeyName, KeyValue);  end;  procedure GetKeyValue(KeyName: Text) KeyValue: Text  begin    if KeyValues.ContainsKey(KeyName) then      exit(KeyValues.Get(KeyName))    else      exit('');  end;  procedure RemoveKeyValue(KeyName: Text)  begin    if KeyValues.ContainsKey(KeyName) then      KeyValues.Remove(KeyName);  end;}