pass ushort as discriminator

src/Discord.Net.Core/CDN.cs

@@ -13,14 +13,9 @@ namespace Discord
             string extension = FormatToExtension(format, avatarId);
             return $"{DiscordConfig.CDNUrl}avatars/{userId}/{avatarId}.{extension}?size={size}";
         }
-        public static string GetDefaultUserAvatarUrl(string discriminator)
+        public static string GetDefaultUserAvatarUrl(ushort discriminator)
         {
-            if (string.IsNullOrEmpty(discriminator))
-                throw new ArgumentNullException(nameof(discriminator));
-
-            int discriminator_mod = Convert.ToInt32(discriminator) % 5;
-
-            return $"{DiscordConfig.CDNUrl}embed/avatars/{discriminator_mod}";
+            return $"{DiscordConfig.CDNUrl}embed/avatars/{discriminator % 5}.png";
         }
         public static string GetGuildIconUrl(ulong guildId, string iconId)
             => iconId != null ? $"{DiscordConfig.CDNUrl}icons/{guildId}/{iconId}.jpg" : null;

src/Discord.Net.Rest/Entities/Users/RestUser.cs

@@ -61,7 +61,7 @@ namespace Discord.Rest
             => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
 
         public string GetDefaultAvatarUrl()
-            => CDN.GetDefaultUserAvatarUrl(Discriminator);
+            => CDN.GetDefaultUserAvatarUrl(ushort.Parse(Discriminator));
 
         public override string ToString() => $"{Username}#{Discriminator}";
         private string DebuggerDisplay => $"{Username}#{Discriminator} ({Id}{(IsBot ? ", Bot" : "")})";

src/Discord.Net.WebSocket/Entities/Users/SocketUser.cs

@@ -62,7 +62,7 @@ namespace Discord.WebSocket
             => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
 
         public string GetDefaultAvatarUrl()
-            => CDN.GetDefaultUserAvatarUrl(Discriminator);
+            => CDN.GetDefaultUserAvatarUrl(ushort.Parse(Discriminator));
 
         public override string ToString() => $"{Username}#{Discriminator}";
         private string DebuggerDisplay => $"{Username}#{Discriminator} ({Id}{(IsBot ? ", Bot" : "")})";