internal static MainActivity Instance { get; private set; }
public override void OnCreate()
{
  base.OnCreate();


//Other code
Instance = this;
 var startMarketingSdk = new StartMCSdk();
 startMarketingSdk.StartSdk();
}

using System;
using Android.Runtime;
using xxxxx.Droid.MessagingServices.MCListener;
using Com.Salesforce.Marketingcloud;
using Com.Salesforce.Marketingcloud.Notifications;
using Com.Salesforce.Marketingcloud.Sfmcsdk;

namespace xxxxx.Droid.MessagingServices
{
  [Preserve(AllMembers = true)]
  public class StartMCSdk : Java.Lang.Object, ISFMCSdkReadyListener, ILogListener
  {
      public void StartSdk()
      {
          try
          {
              // Initialize logging _before_ initializing the SDK to avoid losing valuable debugging information.
#if DEBUG
              SFMCSdk.SetLogging(LogLevel.Debug, this);
              MarketingCloudSdk.LogLevel = MCLogListener.Verbose;
              MarketingCloudSdk.SetLogListener(new MCWriteLogListener());
#endif

               var appID = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
               var accessToken = "xxxxxxxxxxxxxxxxx";
               var appEndpoint = "https://mcxxxxxxxxxxx.device.marketingcloudapis.com/";
               var mid = "0000000000";
               var senderId = "0000000000";
               var inbox = true;
               var pushAnalytics = true;

              var marketingCloudConfig = MarketingCloudConfig
                     .InvokeBuilder()
                     .SetApplicationId(appID)
                     .SetAccessToken(accessToken)
                     .SetSenderId(senderId)
                     .SetMid(mid)
                     .SetGeofencingEnabled(true)
                     .SetDelayRegistrationUntilContactKeyIsSet(true)
                     .SetAnalyticsEnabled(pushAnalytics)
                     .SetInboxEnabled(inbox)
                     .SetMarketingCloudServerUrl(appEndpoint)
                     .SetPiAnalyticsEnabled(true)
                     .SetProximityEnabled(true)
                     .SetNotificationCustomizationOptions(NotificationCustomizationOptions.Create(Resource.Mipmap.app_icon))
                     .Build(MainApplication.Instance);

              // Init a SFMCSdk builder
              var config = new SFMCSdkModuleConfig.Builder();
              config.PushModuleConfig = marketingCloudConfig;
              var builder = config.Build();
              SFMCSdk.Configure(MainApplication.Instance, builder);
              SFMCSdk.RequestSdk(this);

              var sdkListner = new MCSdkListner(MainApplication.Instance);
              MarketingCloudSdk.Init(MainApplication.Instance, marketingCloudConfig, sdkListner);

          }
          catch (Exception ex)
          {
              System.Diagnostics.Debug.WriteLine(ex);
          }
      }

      public void Ready(SFMCSdk sdk)
      {
      }

      public void Out(LogLevel level, string tag, string message, Java.Lang.Throwable throwable)
      {
          LogInformation(tag, message);
      }

      void LogInformation(string methodName, object information) => Debug.WriteLine($"\nMethod: {methodName}\nInfo: {information}");
  }
}

using System;
using System.Diagnostics;
using Android.Runtime;
using Com.Salesforce.Marketingcloud;
using Java.Interop;
using Java.Lang;

namespace xxxxx.Droid.MessagingServices.MCListener
{
    [Preserve(AllMembers = true)]
    class MCWriteLogListener : Java.Lang.Object, IMCLogListener, IJavaObject, IDisposable, IJavaPeerable
    {
        public void Out(int level, string tag, string message, Throwable throwable)
        {
            LogInformation(tag, message);

        }
        void LogInformation(string methodName, object information) => Debug.WriteLine($"\nMethod: {methodName}\nInfo: {information}");

    }
}

using System;
using System.Threading.Tasks;
using Android.App;
using Android.Gms.Common;
using Android.Runtime;
using Com.Salesforce.Marketingcloud;

namespace xxxxx.Droid.MessagingServices
{
    [Preserve(AllMembers = true)]
    public class MCSdkListner : Java.Lang.Object, MarketingCloudSdk.IInitializationListener
    {
        private readonly Application _application;
        private readonly TaskCompletionSource<string> _taskCompletionSource;

        public MCSdkListner(Application application)
        {
            _application = application;
            _taskCompletionSource = new TaskCompletionSource<string>();
        }

        public void Complete(InitializationStatus status)
        {
            if (status.IsUsable)
            {
                var invokedStatus = status.InvokeStatus();

                if (invokedStatus == InitializationStatus.Status.CompletedWithDegradedFunctionality)
                {

                    if (status.LocationsError())
                    {
                        GoogleApiAvailability.Instance.ShowErrorNotification(_application, status.PlayServicesStatus());
                    }
                    else if (status.MessagingPermissionError())
                    {

                        System.Diagnostics.Debug.WriteLine("Location permission was denied.");
                    }
                }

                _taskCompletionSource.TrySetResult(default(string));
            }
            else
            {

                var error = status.UnrecoverableException();
                System.Diagnostics.Debug.WriteLine(error);
                _taskCompletionSource.TrySetException(new Exception(error.ToString()));
            }
        }

    }
}

using System;
using Android.Runtime;
using Com.Salesforce.Marketingcloud;

namespace xxxxx.Droid.MessagingServices.MCListener
{
    [Preserve(AllMembers = true)]
    public class MCReadyListener : Java.Lang.Object, MarketingCloudSdk.IWhenReadyListener
    {
        private string _contactKey { get; set; } = string.Empty;
        public MCReadyListener(string contactKey)
        {
            _contactKey = contactKey;
        }

        public void Ready(MarketingCloudSdk sdk)
        {
            System.Diagnostics.Debug.WriteLine(_contactKey);

            MarketingCloudSdk.Instance.PushMessageManager.EnablePush();
            var success = MarketingCloudSdk.Instance.RegistrationManager.Edit().SetContactKey(_contactKey).Commit();
            string contactkey = MarketingCloudSdk.Instance.RegistrationManager.ContactKey;
            var sdkstate1 = sdk.SdkState.ToString();
        }
    }
}

public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
{

//Other Code
 var startMarketingSDK = new StartMCSdk();
 startMarketingSDK.MarketingSdk();
}


[Export("application:didRegisterForRemoteNotificationsWithDeviceToken:")]
public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
{
    Messaging.SharedInstance.ApnsToken = deviceToken;
    SFMCSdk.Mp.SetDeviceToken(deviceToken);
}

[Export("userNotificationCenter:didReceiveNotificationResponse:withCompletionHandler:")]
public void DidReceiveNotificationResponse(UNUserNotificationCenter center, UNNotificationResponse response, Action completionHandler)
{
    MobilePushSDK.SharedInstance().Sfmc_setNotificationRequest(response.Notification.Request);
    //SFMCSdk.Mp.NotificationRequest(response.Notification.Request);
    completionHandler?.Invoke();
}


// iOS >=10, Fires when application recieves a notification while in the foreground
[Export("userNotificationCenter:willPresentNotification:withCompletionHandler:")]
public static void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)
{
   MobilePushSDK.SharedInstance().Sfmc_setNotificationRequest(notification.Request);
}

// iOS <=9, Fires when application recieves a notification while in the foreground
[Export("application:didReceiveRemoteNotification:fetchCompletionHandler:")]
public override void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
{
    var request = UNNotificationRequest.FromIdentifier(new NSUuid().ToString(), new UNMutableNotificationContent { UserInfo = userInfo }, null);
    MobilePushSDK.SharedInstance().Sfmc_setNotificationUserInfo(userInfo);
    completionHandler.Invoke(UIBackgroundFetchResult.NewData);
}

using Foundation;
using System;
using System.Diagnostics;
using UIKit;
using UserNotifications;
using SFMCiOS;

namespace xxxxx.iOS.MessagingServices
{
    [Preserve(AllMembers = true)]
    public class StartMCSdk
    {
        public void MarketingSdk()
        {
            try
            {
                var appID = "xxxxxx-xxxx-xxx-xx-xxxxxx";
                var accessToken = "xxxxxxx";
                var appEndpoint = "https://mcxxxxxxxx.device.marketingcloudapis.com/";
                var mid = "xxxxxx";
        
                // Define features of MobilePush your app will use.
                var inbox = true;
                var location = false;
                var pushAnalytics = true;

#if DEBUG
                SFMCSdk.SetLoggerWithLogLevel(SFMCSdkLogLevel.Debug, new SFMCSdkLogger());
#endif

                // Use the Mobile Push Config Builder to configure the Mobile Push Module. This gives you the maximum flexibility in SDK configuration.
                // The builder lets you configure the module parameters at runtime.
                var mobilePushConfiguration = new PushConfigBuilder(appID)
                    .SetAccessToken(accessToken)
                    .SetMarketingCloudServerUrl(appEndpoint)
                    .SetMid(mid)
                    .SetInboxEnabled(inbox)
                    .SetLocationEnabled(location)
                    .SetAnalyticsEnabled(pushAnalytics)
                    .Build;


                // Set the completion handler to take action when module initialization is completed. The result indicates if initialization was sucesfull or not.
                // Seting the completion handler is optional.
                Action<SFMCSdkOperationResult> completionHandler = (result) =>
                {
                    if (result == SFMCSdkOperationResult.Success)
                    {
                        LogInformation("CompletionHandler", result);

                        SFMCSdk.Mp.PushEnabled = true;
                        SFMCSdk.Mp.SetURLHandlingDelegate(new URLHandlingDelegate());

                    }
                    else if (result == SFMCSdkOperationResult.Error)
                    {
                        LogInformation("CompletionHandler", result);
                    }
                    else if (result == SFMCSdkOperationResult.Cancelled)
                    {
                        LogInformation("CompletionHandler", result);
                    }
                    else if (result == SFMCSdkOperationResult.Timeout)
                    {
                        LogInformation("CompletionHandler", result);
                    }
                };

                //// Once you've created the mobile push configuration, intialize the SDK.
                SFMCSdk.InitializeSdk(new SFMCSdkConfigBuilder().SetPushWithConfig(mobilePushConfiguration, completionHandler).Build);

                if (UIApplication.SharedApplication.BackgroundRefreshStatus == UIBackgroundRefreshStatus.Available)
                {
                    Debug.WriteLine("Enabling background refresh");
                    UIApplication.SharedApplication.SetMinimumBackgroundFetchInterval(UIApplication.BackgroundFetchIntervalMinimum);
                }
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex);
            }
        }

        void LogInformation(string methodName, object information) => Debug.WriteLine($"\nResult: {methodName}\nInfo: {information}");
    }
}

using System;
using System.Diagnostics;
using SFMCiOS;

namespace xxxxx.iOS.MessagingServices
{
    public class SFMCSdkLogger : SFMCSdkLogOutputter
    {
        public override void OutWithLevel(SFMCSdkLogLevel level, string subsystem, SFMCSdkLoggerCategory category, string message)
        {
            LogInformation(subsystem, message);
        }

        void LogInformation(string methodName, object information) => Debug.WriteLine($"\nSubsystem: {methodName}\nInfo: {information}");
    }
}

using System;
using System.Diagnostics;
using Foundation;
using SFMCiOS;
using UIKit;

namespace xxxxx.iOS.MessagingServices
{
    public class URLHandlingDelegate : SFMCSdkURLHandlingDelegate
    {
        public override void Type(NSUrl url, string type)
        {
            Debug.WriteLine(string.Format("HandleURL: {0} {1}", type, url));

            if (UIApplication.SharedApplication.CanOpenUrl(url))
            {
                Debug.WriteLine(string.Format("Can open: " + url));
                var options = new NSDictionary();
                UIApplication.SharedApplication.OpenUrl(url, options, (success) => Debug.WriteLine("OpenURL: " + success));
            }
            else
            {
                Debug.WriteLine("Cannot open URL: " + url);
            }
        }

    }
}