Add retry helper method

src/libse/Common/Retry.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+namespace Nikse.SubtitleEdit.Core.Common
+{
+    public class Retry
+    {
+        public static void Do(Action action, TimeSpan retryInterval, int maxAttemptCount)
+        {
+            Do<object>(() =>
+            {
+                action();
+                return null;
+            }, retryInterval, maxAttemptCount);
+        }
+
+        public static T Do<T>(Func<T> action, TimeSpan retryInterval, int maxAttemptCount)
+        {
+            var lastException = new Exception();
+            for (int attempted = 0; attempted < maxAttemptCount; attempted++)
+            {
+                try
+                {
+                    if (attempted > 0)
+                    {
+                        Thread.Sleep(retryInterval);
+                    }
+                    return action();
+                }
+                catch (Exception ex)
+                {
+                    lastException = ex;
+                }
+            }
+
+            throw lastException;
+        }
+    }
+}