Implement the sync callable dispatch for the main queue.
Implement the sync callable dispatch for the main queue.

EuropeanSpallationSource/openxal,luxiaohan/openxal-csns-luxh,openxal/openxal,openxal/openxal,EuropeanSpallationSource/openxal,openxal/openxal,openxal/openxal,EuropeanSpallationSource/openxal,EuropeanSpallationSource/openxal,luxiaohan/openxal-csns-luxh,EuropeanSpallationSource/openxal,luxiaohan/openxal-csns-luxh,openxal/openxal,luxiaohan/openxal-csns-luxh