in FBSDKCoreKit/FBSDKCoreKit/FBSDKInternalUtility.m [50:55]
static BOOL ShouldOverrideHostWithGamingDomain(NSString *hostPrefix)
{
return [FBSDKAuthenticationToken.currentAuthenticationToken respondsToSelector:@selector(graphDomain)]
&& [FBSDKAuthenticationToken.currentAuthenticationToken.graphDomain isEqualToString:@"gaming"]
&& ([hostPrefix isEqualToString:@"graph."] || [hostPrefix isEqualToString:@"graph-video."]);
}