Hello Xamarin Folks,
I am stuck with a very unpredictive error form last couple of months.
It all started when I updated my Visual Studio for Mac and other components of Xamarin Platform. I glad one of my team member didn't update and we are all depended on him to generate build for iOS.
Problem:
If I build iOS project with Release configuration/iPhone Device I get following error,
clang : error : linker command failed with exit code 1 (use -v to see invocation)
MTOUCH : error MT5211: Native linking failed, undefined Objective-C class: TAGContainerCallback. The symbol 'OBJC_CLASS$TAGContainerCallback' could not be found in any of the libraries or frameworks linked with your application.
MTOUCH : error MT5211: Native linking failed, undefined Objective-C class: TAGLogger. The symbol '_OBJC_CLASS$TAGLogger' could not be found in any of the libraries or frameworks linked with your application.
MTOUCH : error MT5211: Native linking failed, undefined Objective-C class: GAILogger. The symbol '_OBJC_CLASS$_GAILogger' could not be found in any of the libraries or frameworks linked with your application.
MTOUCH : error MT5202: Native linking failed. Please review the build log.
Although the application is working in Debug configuration on iPhoneSimulator.
I tried updating Xamarin.Forms, Xamarin.Forms.Maps, Xamarin.Google.Maps to the latest version in all my relevant project. No success. 
From my findings: TAGContainerCallback, TAGLogger and GAILogger belong to Maps control or Picker control.
Any information or hint is appreciated.