如何在Objective-C中将数据从反向编码保存到CoreData？

I am trying to do reverse-geocoding with current location, retrieve City and State and save it to CoreData entity. In the below code, as soon as the save button is hit by user, I expect reverse geocoding to take place and save city and state information to Core Data. But when I try to execute below code, reverse geocoding part is not executed and no data is saved to Core Data. One pointer that I found in other threads is that reverse-geocoding takes place in an independent thread and later part of this function gets kicked in without reverse geocoding taking place. Can someone please guide me on how to proceed with this problem? I'm still new to iOS app development, so detailed reply would be highly appreciated. Thanks in advance! I am trying to do reverse-geocoding with curren