Changed snowflakes to be wrapped in an optional instead of a nullable.

src/Discord.Net.Core/Entities/Messages/MessageReference.cs

@@ -11,7 +11,7 @@ namespace Discord
         /// <summary>
         ///     Gets the Message ID of the original message.
         /// </summary>
-        public ulong? MessageId { get; internal set; }
+        public Optional<ulong> MessageId { get; internal set; }
 
         /// <summary>
         ///     Gets the Channel ID of the original message.
@@ -21,11 +21,11 @@ namespace Discord
         /// <summary>
         ///     Gets the Guild ID of the original message.
         /// </summary>
-        public ulong? GuildId { get; internal set; }
+        public Optional<ulong> GuildId { get; internal set; }
 
         private string DebuggerDisplay
-            => $"Channel ID: ({ChannelId}){(GuildId.HasValue ? $", Guild ID: ({GuildId.Value})" : "")}" +
-            $"{(MessageId.HasValue ? $", Message ID: ({MessageId.Value})" : "")}";
+            => $"Channel ID: ({ChannelId}){(GuildId.IsSpecified ? $", Guild ID: ({GuildId.Value})" : "")}" +
+            $"{(MessageId.IsSpecified ? $", Message ID: ({MessageId.Value})" : "")}";
 
         public override string ToString()
             => DebuggerDisplay;

src/Discord.Net.Rest/API/Common/MessageReference.cs

@@ -5,12 +5,12 @@ namespace Discord.API
     internal class MessageReference
     {
         [JsonProperty("message_id")]
-        public ulong? MessageId { get; set; }
+        public Optional<ulong> MessageId { get; set; }
 
         [JsonProperty("channel_id")]
         public ulong ChannelId { get; set; }
 
         [JsonProperty("guild_id")]
-        public ulong? GuildId { get; set; }
+        public Optional<ulong> GuildId { get; set; }
     }
 }