AppDelegate.m error while building: Use of undeclared identifier '_trustKitConfig'

Question

Here's what I have in AppDelegate.m:

#import "AppDelegate.h"

#import <React/RCTBridge.h>
#import <React/RCTBundleURLProvider.h>
#import <React/RCTRootView.h>
#import <React/RCTLinkingManager.h>
#import <React/RCTConvert.h>
#import "RNSplashScreen.h"  // here
#import <TrustKit/TrustKit.h>
#import <TrustKit/TSKPinningValidator.h>
#import <TrustKit/TSKPinningValidatorCallback.h>

#if defined(FB_SONARKIT_ENABLED) && __has_include(<FlipperKit/FlipperClient.h>)
#import <FlipperKit/FlipperClient.h>
#import <FlipperKitLayoutPlugin/FlipperKitLayoutPlugin.h>
#import <FlipperKitUserDefaultsPlugin/FKUserDefaultsPlugin.h>
#import <FlipperKitNetworkPlugin/FlipperKitNetworkPlugin.h>
#import <SKIOSNetworkPlugin/SKIOSNetworkAdapter.h>
#import <FlipperKitReactPlugin/FlipperKitReactPlugin.h>


static void InitializeFlipper(UIApplication *application) {
  FlipperClient *client = [FlipperClient sharedClient];
  SKDescriptorMapper *layoutDescriptorMapper = [[SKDescriptorMapper alloc] initWithDefaults];
  [client addPlugin:[[FlipperKitLayoutPlugin alloc] initWithRootNode:application withDescriptorMapper:layoutDescriptorMapper]];
  [client addPlugin:[[FKUserDefaultsPlugin alloc] initWithSuiteName:nil]];
  [client addPlugin:[FlipperKitReactPlugin new]];
  [client addPlugin:[[FlipperKitNetworkPlugin alloc] initWithNetworkAdapter:[SKIOSNetworkAdapter new]]];
  [client start];
}
#endif

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  //....some configurations
  [RNSplashScreen show];
  NSDictionary *trustKitConfig =
  @{
    kTSKPinnedDomains : @{
            @"www.google.com" : @{
                    kTSKEnforcePinning : @YES,
                    kTSKIncludeSubdomains: @YES,
                    kTSKPublicKeyHashes : @[
                            @"2wWi1236zqwqwqeqqeqeqeq0eAwgmNBg=",
                            ],
                    },
            }};
   [TrustKit initSharedInstanceWithConfiguration:trustKitConfig];
   trustKit = [TrustKit sharedInstance];
  return YES;
 }

The error I am getting

Trying to find a way to what I am doing wrong. Pods are installed and there is only a need to fix appdelagate.m . Need to add ssl pinning in react native app using trustkit