Added func-based UsingXXX extensions

src/Discord.Net.Audio/AudioExtensions.cs

@@ -1,4 +1,6 @@
-namespace Discord.Audio
+using System;
+
+namespace Discord.Audio
 {
     public static class AudioExtensions
     {
@@ -7,7 +9,14 @@
             client.Services.Add(new AudioService(config));
             return client;
         }
-		public static AudioService Audio(this DiscordClient client, bool required = true)
+        public static DiscordClient UsingAudio(this DiscordClient client, Action<AudioServiceConfig> configFunc = null)
+        {
+            var config = new AudioServiceConfig();
+            configFunc(config);
+            client.Services.Add(new AudioService(config));
+            return client;
+        }
+        public static AudioService Audio(this DiscordClient client, bool required = true)
 			=> client.Services.Get<AudioService>(required);
     }
 }

src/Discord.Net.Commands/CommandExtensions.cs

@@ -1,4 +1,6 @@
-namespace Discord.Commands
+using System;
+
+namespace Discord.Commands
 {
     public static class CommandExtensions
     {
@@ -7,6 +9,13 @@
             client.Services.Add(new CommandService(config));
             return client;
         }
+        public static DiscordClient UsingCommands(this DiscordClient client, Action<CommandServiceConfig> configFunc = null)
+        {
+            var config = new CommandServiceConfig();
+            configFunc(config);
+            client.Services.Add(new CommandService(config));
+            return client;
+        }
         public static CommandService Commands(this DiscordClient client, bool required = true)
 			=> client.Services.Get<CommandService>(required);
     }

src/Discord.Net.Modules/ModuleExtensions.cs

@@ -7,6 +7,7 @@
             client.Services.Add(new ModuleService());
             return client;
         }
+
         public static DiscordClient AddModule<T>(this DiscordClient client, T instance, string name = null, ModuleFilter filter = ModuleFilter.None)
             where T : class, IModule
         {