SnackBar_Customized.cs

 //customized snackbar
 void fnSnackBar( string strText,bool isLengthIndefinite)
	{ 
	Snackbar objSnackBar = Snackbar.Make (linearLayoutMain, strText, isLengthIndefinite ? Snackbar.LengthIndefinite : Snackbar.LengthShort)
		.SetAction (Resource.String.retry, (v) => {
		//set action
		}); 
	//set  action button text color 
	objSnackBar.SetActionTextColor(Android.Graphics.Color.Aqua); 
	
	Android.Views.View objView = objSnackBar.View; 
	TextView txtAction = objView.FindViewById<TextView> (Resource.Id.snackbar_action);
	txtAction.SetTextSize (Android.Util.ComplexUnitType.Dip, 18);

	//set message text color
	TextView txtMessage = objView.FindViewById<TextView> (Resource.Id.snackbar_text);
	txtMessage.SetTextColor (Android.Graphics.Color.Red);
	txtMessage.SetTextSize (Android.Util.ComplexUnitType.Dip, 18);
			
     	objSnackBar.Show ();
        }