Add UpdateStarted event to signal when update download begins

AlwaysUpToDate.Test/Program.cs

@@ -11,6 +11,7 @@ internal class Program
     {
         updater.ProgressChanged += Updater_ProgressChanged;
         updater.UpdateAvailable += Updater_UpdateAvailable;
+        updater.UpdateStarted += Updater_UpdateStarted;
         updater.NoUpdateAvailable += Updater_NoUpdateAvailable;
         updater.OnException += Updater_OnException;
         updater.Start();
@@ -42,6 +43,11 @@ internal class Program
         Console.WriteLine($"[{step}] {itemsProcessed}/{totalItems}  {progressPercentage}%");
     }
 
+    private static void Updater_UpdateStarted(string version)
+    {
+        Console.WriteLine($"Starting update to version {version}...");
+    }
+
     private static void Updater_NoUpdateAvailable()
     {
         Console.WriteLine("You are up to date!");

AlwaysUpToDate/DownloadManager.cs

@@ -66,6 +66,17 @@ namespace AlwaysUpToDate
         /// </summary>
         public event ExceptionHandler OnException;
 
+        /// <summary>
+        /// Represents the method that will handle notifications when the update process begins.
+        /// </summary>
+        /// <param name="version">The version string of the update being installed.</param>
+        public delegate void UpdateStartedHandler(string version);
+
+        /// <summary>
+        /// Occurs once when the update download begins, before the first <see cref="ProgressChanged"/> event.
+        /// </summary>
+        public event UpdateStartedHandler UpdateStarted;
+
         private static readonly XmlSerializer manifestSerializer = new XmlSerializer(typeof(UpdateManifest));
         private readonly HttpClient httpClient = new HttpClient();
         private readonly System.Timers.Timer updateTimer = new System.Timers.Timer();
@@ -242,6 +253,8 @@ namespace AlwaysUpToDate
                 updateTimer.Stop();
                 _ = Interlocked.Exchange(ref updating, 1);
 
+                UpdateStarted?.Invoke(pendingUpdateItem?.Version);
+
                 using HttpResponseMessage response = await httpClient.GetAsync(updateUrl);
                 _ = response.EnsureSuccessStatusCode();
 

README.md

@@ -51,12 +51,17 @@ updater.Start();
 ...
     updater.ProgressChanged += Updater_ProgressChanged;
     updater.UpdateAvailible += Updater_UpdateAvailible;
+    updater.UpdateStarted += Updater_UpdateStarted;
 }
 
 private static void Updater_UpdateAvailible(string version, string additionalInformationUrl)
 {
 }
 
+private static void Updater_UpdateStarted(string version)
+{
+}
+
 private static void Updater_ProgressChanged(UpdateStep step, long? totalItems, long itemsProcessed, double? progressPercentage)
 {  
 }