Exception: No such proxy method: GooglePlayGames.Android.AndroidTokenClient+ResultCallbackProxy

 [Play Games Plugin DLL] 01/31/19 13:56:56 +09:00 DEBUG: Activating PlayGamesPlatform.

I/Unity   ( 4520):

I/Unity   ( 4520): (Filename: ./Runtime/Export/Debug.bindings.h Line: 43)

I/Unity   ( 4520):

I/Unity   ( 4520):  [Play Games Plugin DLL] 01/31/19 13:56:56 +09:00 DEBUG: PlayGamesPlatform activated: GooglePlayGames.PlayGamesPlatform

I/Unity   ( 4520):

I/Unity   ( 4520): (Filename: ./Runtime/Export/Debug.bindings.h Line: 43)

I/Unity   ( 4520):

I/Unity   ( 4520):  [Play Games Plugin DLL] 01/31/19 13:56:56 +09:00 DEBUG: Creating platform-specific Play Games client.

I/Unity   ( 4520):

I/Unity   ( 4520): (Filename: ./Runtime/Export/Debug.bindings.h Line: 43)

I/Unity   ( 4520):

I/Unity   ( 4520):  [Play Games Plugin DLL] 01/31/19 13:56:56 +09:00 DEBUG: Creating Android IPlayGamesClient Client

I/Unity   ( 4520):

I/Unity   ( 4520): (Filename: ./Runtime/Export/Debug.bindings.h Line: 43)

I/Unity   ( 4520):

E/Unity   ( 4520): Java interface default methods are only supported since Android Oreo

E/Unity   ( 4520): Exception: No such proxy method: GooglePlayGames.Android.AndroidTokenClient+ResultCallbackProxy.toString()

E/Unity   ( 4520):   at UnityEngine.AndroidJavaProxy.Invoke (System.String methodName, System.Object[] args) [0x00000] in <filename unknown>:0

E/Unity   ( 4520):   at UnityEngine.AndroidJavaProxy.Invoke (System.String methodName, UnityEngine.AndroidJavaObject[] javaArgs) [0x00000] in <filename unknown>:0

E/Unity   ( 4520):   at UnityEngine._AndroidJNIHelper.InvokeJavaProxyMethod (UnityEngine.AndroidJavaProxy proxy, IntPtr jmethodName, IntPtr jargs) [0x00000] in <filename unknown>:0

E/Unity   ( 4520):

E/Unity   ( 4520): (Filename:  Line: -1)

E/Unity   ( 4520):

I/Unity   ( 4520): Building GPG services, implicitly attempts silent auth

I/Unity   ( 4520):

I/Unity   ( 4520): (Filename: ./Runtime/Export/Debug.bindings.h Line: 43)

I/Unity   ( 4520):

I/Unity   ( 4520):  [Play Games Plugin DLL] 01/31/19 13:56:58 +09:00 DEBUG: Starting Auth Transition. Op: SIGN_IN status: VALID

I/Unity   ( 4520):

I/Unity   ( 4520): (Filename: ./Runtime/Export/Debug.bindings.h Line: 43)

I/Unity   ( 4520):

I/Unity   ( 4520):  [Play Games Plugin DLL] 01/31/19 13:56:58 +09:00 DEBUG: Entering internal callback for PlayerManager#InternalFetchSelfCallback

GPGS 로그인시 Exception 발생 

해결방법 

https://github.com/playgameservices/play-games-plugin-for-unity/issues/29

빌드를 IL2CPP로...

IL2CPP

https://docs.unity3d.com/kr/2018.1/Manual/IL2CPP.html

IL2CPP와 Exception과의 관계는??