Index: Src/GoogleApis.Auth/OAuth2/Flows/AuthorizationCodeFlow.cs
===================================================================
--- a/Src/GoogleApis.Auth/OAuth2/Flows/AuthorizationCodeFlow.cs
+++ b/Src/GoogleApis.Auth/OAuth2/Flows/AuthorizationCodeFlow.cs
@@ -264,6 +264,11 @@
             return token;
         }
 
+        public virtual Task RevokeTokenAsync(string userId, string token, CancellationToken taskCancellationToken)
+        {
+            throw new NotImplementedException("The OAuth 2.0 protocol does not support token revocation.");
+        }
+
         #endregion
 
         /// <summary>Stores the token in the <see cref="DataStore"/>.</summary>