reuse code

src/iOS.Core/Views/ExtensionSearchDelegate.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Foundation;
+using UIKit;
+
+namespace Bit.iOS.Core.Views
+{
+    public class ExtensionSearchDelegate : UISearchBarDelegate
+    {
+        private readonly UITableView _tableView;
+        private CancellationTokenSource _filterResultsCancellationTokenSource;
+
+        public ExtensionSearchDelegate(UITableView tableView)
+        {
+            _tableView = tableView;
+        }
+
+        public override void TextChanged(UISearchBar searchBar, string searchText)
+        {
+            var cts = new CancellationTokenSource();
+            Task.Run(() =>
+            {
+                NSRunLoop.Main.BeginInvokeOnMainThread(async () =>
+                {
+                    if(!string.IsNullOrWhiteSpace(searchText))
+                    {
+                        await Task.Delay(300);
+                        if(searchText != searchBar.Text)
+                        {
+                            return;
+                        }
+                        else
+                        {
+                            _filterResultsCancellationTokenSource?.Cancel();
+                        }
+                    }
+                    try
+                    {
+                        ((ExtensionTableSource)_tableView.Source).FilterResults(searchText, cts.Token);
+                        _tableView.ReloadData();
+                    }
+                    catch(OperationCanceledException) { }
+                    _filterResultsCancellationTokenSource = cts;
+                });
+            }, cts.Token);
+        }
+    }
+}