feature: adjust the ratelimit for reactions

allows users to add reactions quickly

src/Discord.Net.Core/RequestOptions.cs

@@ -1,4 +1,4 @@
-using System.Threading;
+using System.Threading;
 
 namespace Discord
 {
@@ -22,6 +22,7 @@ namespace Discord
         internal bool IgnoreState { get; set; }
         internal string BucketId { get; set; }
         internal bool IsClientBucket { get; set; }
+        internal bool IsReactionBucket { get; set; }
 
         internal static RequestOptions CreateOrClone(RequestOptions options)
         {            

src/Discord.Net.Rest/DiscordRestApiClient.cs

@@ -583,6 +583,7 @@ namespace Discord.API
             Preconditions.NotNullOrWhitespace(emoji, nameof(emoji));
 
             options = RequestOptions.CreateOrClone(options);
+            options.IsReactionBucket = true;
 
             var ids = new BucketIds(channelId: channelId);
 
@@ -595,6 +596,7 @@ namespace Discord.API
             Preconditions.NotNullOrWhitespace(emoji, nameof(emoji));
 
             options = RequestOptions.CreateOrClone(options);
+            options.IsReactionBucket = true;
 
             var ids = new BucketIds(channelId: channelId);
 

src/Discord.Net.Rest/Net/Queue/RequestQueueBucket.cs

@@ -1,3 +1,4 @@
+#define DEBUG_LIMITS
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 using System;
@@ -250,6 +251,10 @@ namespace Discord.Net.Queue
                 else if (info.Reset.HasValue)
                 {
                     resetTick = info.Reset.Value.AddSeconds(info.Lag?.TotalSeconds ?? 1.0);
+
+                    if (request.Options.IsReactionBucket)
+                        resetTick = new DateTimeOffset(resetTick.Value.Ticks / 4, TimeSpan.Zero);
+
                     int diff = (int)(resetTick.Value - DateTimeOffset.UtcNow).TotalMilliseconds;
 #if DEBUG_LIMITS
                     Debug.WriteLine($"[{id}] X-RateLimit-Reset: {info.Reset.Value.ToUnixTimeSeconds()} ({diff} ms, {info.Lag?.TotalMilliseconds} ms lag)");