Implement enforced nonces (#113)

* Implement enforced nonces

* Update extension, param name and docs

* Opps

* Review changes

Author: AnotherZane

src/Disqord.Core/Entities/Local/Message/Extensions/LocalMessageExtensions.cs

@@ -61,15 +61,37 @@ public static TMessage WithReply<TMessage>(this TMessage message, Snowflake mess
     /// </remarks>
     /// <param name="message"> The <see cref="LocalMessage"/> instance. </param>
     /// <param name="nonce"> The nonce. </param>
+    /// <param name="shouldEnforceNonce"> Whether the nonce should be enforced. </param>
     /// <typeparam name="TMessage"> The <see cref="LocalMessage"/> type. </typeparam>
     /// <returns>
     ///     The input instance.
     /// </returns>
     /// <seealso cref="LocalMessage.Nonce"/>
-    public static TMessage WithNonce<TMessage>(this TMessage message, string nonce)
+    public static TMessage WithNonce<TMessage>(this TMessage message, string nonce, bool shouldEnforceNonce = false)
         where TMessage : LocalMessage
     {
         message.Nonce = nonce;
+        message.ShouldEnforceNonce = Optional.Conditional(shouldEnforceNonce, true);
+        return message;
+    }
+
+    /// <summary>
+    ///     Sets whether the uniqueness check of a nonce should be enforced on this message.
+    /// </summary>
+    /// <remarks>
+    ///     <inheritdoc cref="LocalMessage.ShouldEnforceNonce"/>
+    /// </remarks>
+    /// <param name="message"> The <see cref="LocalMessage"/> instance. </param>
+    /// <param name="shouldEnforceNonce"> Whether the nonce should be enforced. </param>
+    /// <typeparam name="TMessage"> The <see cref="LocalMessage"/> type. </typeparam>
+    /// <returns>
+    ///     The input instance.
+    /// </returns>
+    /// <seealso cref="LocalMessage.ShouldEnforceNonce"/>
+    public static TMessage WithShouldEnforceNonce<TMessage>(this TMessage message, bool shouldEnforceNonce = true)
+        where TMessage : LocalMessage
+    {
+        message.ShouldEnforceNonce = shouldEnforceNonce;
         return message;
     }
 }

src/Disqord.Core/Entities/Local/Message/LocalMessage.cs

@@ -25,6 +25,14 @@ public class LocalMessage : LocalMessageBase, ILocalConstruct<LocalMessage>
     /// </remarks>
     public Optional<string> Nonce { get; set; }
 
+    /// <summary>
+    ///     Gets or sets whether the uniqueness check of a nonce should be enforced.
+    /// </summary>
+    /// <remarks>
+    ///     If set to true and another message with the same nonce was sent recently, the message will not be sent.
+    /// </remarks>
+    public Optional<bool> ShouldEnforceNonce { get; set; }
+
     /// <summary>
     ///     Instantiates a new <see cref="LocalMessage"/>.
     /// </summary>
@@ -40,6 +48,7 @@ protected LocalMessage(LocalMessage other)
     {
         Reference = other.Reference.Clone();
         Nonce = other.Nonce;
+        ShouldEnforceNonce = other.ShouldEnforceNonce;
     }
 
     /// <inheritdoc/>

src/Disqord.Rest.Api/Content/Json/CreateMessageJsonRestRequestContent.cs

@@ -37,6 +37,9 @@ public class CreateMessageJsonRestRequestContent : JsonModelRestRequestContent,
     [JsonProperty("flags")]
     public Optional<MessageFlags> Flags;
 
+    [JsonProperty("enforce_nonce")]
+    public Optional<bool> EnforceNonce;
+
     IList<PartialAttachmentJsonModel> IAttachmentRestRequestContent.Attachments
     {
         set => Attachments = new(value);

src/Disqord.Rest/Extensions/RestClientExtensions.Channel.cs

@@ -261,7 +261,8 @@ public static async Task<IUserMessage> SendMessageAsync(this IRestClient client,
             MessageReference = Optional.Convert(message.Reference, reference => reference.ToModel()),
             Components = Optional.Convert(message.Components, components => components.Select(component => component.ToModel()).ToArray()),
             StickerIds = Optional.Convert(message.StickerIds, stickerIds => stickerIds.ToArray()),
-            Flags = message.Flags
+            Flags = message.Flags,
+            EnforceNonce = message.ShouldEnforceNonce
         };
 
         Task<MessageJsonModel> task;
@@ -649,7 +650,8 @@ public static async Task<IThreadChannel> CreateForumThreadAsync(this IRestClient
             MessageReference = Optional.Convert(message.Reference, reference => reference.ToModel()),
             Components = Optional.Convert(message.Components, components => components.Select(component => component.ToModel()).ToArray()),
             StickerIds = Optional.Convert(message.StickerIds, stickerIds => stickerIds.ToArray()),
-            Flags = message.Flags
+            Flags = message.Flags,
+            EnforceNonce = message.ShouldEnforceNonce
         };
 
         var forumContent = new CreateForumThreadJsonRestRequestContent