feat: use async event handlers

TcpDotNet.ClientIntegrationTest/Program.cs

@@ -7,7 +7,11 @@ using TcpDotNet.Protocol.Packets.ClientBound;
 using TcpDotNet.Protocol.Packets.ServerBound;
 
 using var client = new ProtocolClient();
-client.Disconnected += (_, e) => Console.WriteLine($"Disconnected: {e.DisconnectReason}");
+client.Disconnected += (_, e) =>
+{
+    Console.WriteLine($"Disconnected: {e.DisconnectReason}");
+    return Task.CompletedTask;
+};
 
 client.RegisterPacketHandler(PacketHandler<PongPacket>.Empty);
 client.RegisterPacketHandler(new GoodbyePacketHandler());

TcpDotNet.ListenerIntegrationTest/Program.cs

@@ -5,8 +5,16 @@ using TcpDotNet.Protocol.Packets.ClientBound;
 using TcpDotNet.Protocol.Packets.ServerBound;
 
 var listener = new ProtocolListener();
-listener.ClientConnected += (_, e) => Console.WriteLine($"Client connected from {e.Client.RemoteEndPoint} with session {e.Client.SessionId}");
+listener.ClientConnected += (_, e) =>
-listener.ClientDisconnected += (_, e) => Console.WriteLine($"Client {e.Client.SessionId} disconnected ({e.DisconnectReason})");
+{
+    Console.WriteLine($"Client connected from {e.Client.RemoteEndPoint} with session {e.Client.SessionId}");
+    return Task.CompletedTask;
+};
+listener.ClientDisconnected += (_, e) =>
+{
+    Console.WriteLine($"Client {e.Client.SessionId} disconnected ({e.DisconnectReason})");
+    return Task.CompletedTask;
+};
 
 listener.RegisterPacketHandler(new HelloPacketHandler());
 listener.RegisterPacketHandler(new PingPacketHandler());

TcpDotNet/AsyncEventHandler.cs

@@ -0,0 +1,16 @@
+namespace TcpDotNet;
+
+/// <summary>
+///     Represents the method that will handle an asynchronous event that has no event data.
+/// </summary>
+/// <param name="sender">The source of the event.</param>
+/// <param name="e">An object that contains no event data.</param>
+public delegate Task AsyncEventHandler(object? sender, EventArgs e);
+
+/// <summary>
+///     Represents the method that will handle an asynchronous event when the event provides data.
+/// </summary>
+/// <typeparam name="TEventArgs">The type of the event data generated by the event.</typeparam>
+/// <param name="sender">The source of the event.</param>
+/// <param name="e">An object that contains event data.</param>
+public delegate Task AsyncEventHandler<in TEventArgs>(object? sender, TEventArgs e);

TcpDotNet/ProtocolClient.cs

@@ -30,7 +30,7 @@ public sealed class ProtocolClient : ClientNode
     /// <summary>
     ///     Occurs when the client has been disconnected.
     /// </summary>
-    public event EventHandler<DisconnectedEventArgs>? Disconnected;
+    public event AsyncEventHandler<DisconnectedEventArgs>? Disconnected;
 
     /// <summary>
     ///     Establishes a connection to a remote host.

TcpDotNet/ProtocolListener.cs

@@ -27,27 +27,27 @@ public sealed partial class ProtocolListener : Node
     /// <summary>
     ///     Occurs when a client connects to the listener.
     /// </summary>
-    public event EventHandler<ClientConnectedEventArgs>? ClientConnected;
+    public event AsyncEventHandler<ClientConnectedEventArgs>? ClientConnected;
 
     /// <summary>
     ///     Occurs when a client disconnects from the listener.
     /// </summary>
-    public event EventHandler<ClientDisconnectedEventArgs>? ClientDisconnected;
+    public event AsyncEventHandler<ClientDisconnectedEventArgs>? ClientDisconnected;
 
     /// <summary>
     ///     Occurs when a client sends a packet to the listener.
     /// </summary>
-    public event EventHandler<ClientPacketReceivedEventArgs>? ClientPacketReceived;
+    public event AsyncEventHandler<ClientPacketReceivedEventArgs>? ClientPacketReceived;
 
     /// <summary>
     ///     Occurs when the server has started.
     /// </summary>
-    public event EventHandler? Started;
+    public event AsyncEventHandler? Started;
 
     /// <summary>
     ///     Occurs when the server has started.
     /// </summary>
-    public event EventHandler? Stopped;
+    public event AsyncEventHandler? Stopped;
 
     /// <summary>
     ///     Gets a read-only view of the clients connected to this listener.