Merge branch 'dev' into feature/reset-fater

This patch applies the changes made to parsing precision in 606dac3.

src/Discord.Net.Core/DiscordConfig.cs

@@ -152,5 +152,23 @@ namespace Discord
         ///     The currently set <see cref="RateLimitPrecision"/>.
         /// </returns>
         public RateLimitPrecision RateLimitPrecision { get; set; } = RateLimitPrecision.Millisecond;
+
+		/// <summary>
+		/// 	Gets or sets whether or not rate-limits should use the system clock.
+		/// </summary>
+		/// <remarks>
+		///		If set to <c>false</c>, we will use the X-RateLimit-Reset-After header
+		///		to determine when a rate-limit expires, rather than comparing the
+		///		X-RateLimit-Reset timestamp to the system time.
+		///
+		///		This should only be changed to false if the system is known to have
+		/// 	a clock that is out of sync. Relying on the Reset-After header will
+		///		incur network lag.
+		///
+		///		Regardless of this property, we still rely on the system's wall-clock
+		///		to determine if a bucket is rate-limited; we do not use any monotonic
+		///		clock. Your system will still need a stable clock.
+		/// </remarks>
+		public bool UseSystemClock { get; set; } = true;
     }
 }

src/Discord.Net.Core/RequestOptions.cs

@@ -44,6 +44,18 @@ namespace Discord
         ///     to all actions.
         /// </remarks>
         public string AuditLogReason { get; set; }
+		/// <summary>
+		///		Gets or sets whether or not this request should use the system
+		///		clock for rate-limiting. Defaults to <c>true</c>.
+		/// </summary>
+		/// <remarks>
+		///		This property can also be set in <see cref="DiscordConfig">.
+		///
+		///		On a per-request basis, the system clock should only be disabled 
+		///		when millisecond precision is especially important, and the
+		///		hosting system is known to have a desynced clock.
+		/// </remarks>
+		public bool? UseSystemClock { get; set; }
 
         internal bool IgnoreState { get; set; }
         internal string BucketId { get; set; }

src/Discord.Net.Rest/DiscordRestApiClient.cs

@@ -46,18 +46,20 @@ namespace Discord.API
         internal IRestClient RestClient { get; private set; }
         internal ulong? CurrentUserId { get; set; }
         public RateLimitPrecision RateLimitPrecision { get; private set; }
+		internal bool UseSystemClock { get; set; }
         
         internal JsonSerializer Serializer => _serializer;
 
         /// <exception cref="ArgumentException">Unknown OAuth token type.</exception>
         public DiscordRestApiClient(RestClientProvider restClientProvider, string userAgent, RetryMode defaultRetryMode = RetryMode.AlwaysRetry,
-            JsonSerializer serializer = null, RateLimitPrecision rateLimitPrecision = RateLimitPrecision.Second)
+            JsonSerializer serializer = null, RateLimitPrecision rateLimitPrecision = RateLimitPrecision.Second, bool useSystemClock = true)
         {
             _restClientProvider = restClientProvider;
             UserAgent = userAgent;
             DefaultRetryMode = defaultRetryMode;
             _serializer = serializer ?? new JsonSerializer { ContractResolver = new DiscordContractResolver() };
             RateLimitPrecision = rateLimitPrecision;
+			UseSystemClock = useSystemClock;
 
             RequestQueue = new RequestQueue();
             _stateLock = new SemaphoreSlim(1, 1);
@@ -265,6 +267,8 @@ namespace Discord.API
                 CheckState();
             if (request.Options.RetryMode == null)
                 request.Options.RetryMode = DefaultRetryMode;
+			if (request.Options.UseSystemClock == null)
+				request.Options.UseSystemClock = UseSystemClock;
 
             var stopwatch = Stopwatch.StartNew();
             var responseStream = await RequestQueue.SendAsync(request).ConfigureAwait(false);

src/Discord.Net.Rest/DiscordRestClient.cs

@@ -28,7 +28,11 @@ namespace Discord.Rest
         internal DiscordRestClient(DiscordRestConfig config, API.DiscordRestApiClient api) : base(config, api) { }
 
         private static API.DiscordRestApiClient CreateApiClient(DiscordRestConfig config)
-            => new API.DiscordRestApiClient(config.RestClientProvider, DiscordRestConfig.UserAgent);
+            => new API.DiscordRestApiClient(config.RestClientProvider, 
+				DiscordRestConfig.UserAgent, 
+				rateLimitPrecision: config.RateLimitPrecision, 
+				useSystemClock: config.UseSystemClock);
+
         internal override void Dispose(bool disposing)
         {
             if (disposing)

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

@@ -247,12 +247,19 @@ namespace Discord.Net.Queue
                     Debug.WriteLine($"[{id}] Retry-After: {info.RetryAfter.Value} ({info.RetryAfter.Value} ms)");
 #endif
                 }
+				else if (info.ResetAfter.HasValue && (request.Options.UseSystemClock.HasValue ? !request.Options.UseSystemClock.Value : false))
+				{
+					resetTick = DateTimeOffset.Now.Add(info.ResetAfter.Value);
+				}
                 else if (info.Reset.HasValue)
                 {
                     resetTick = info.Reset.Value.AddSeconds(info.Lag?.TotalSeconds ?? 1.0);
 
+					/* millisecond precision makes this unnecessary, retaining in case of regression
+
                     if (request.Options.IsReactionBucket)
                         resetTick = DateTimeOffset.Now.AddMilliseconds(250);
+					*/
 
                     int diff = (int)(resetTick.Value - DateTimeOffset.UtcNow).TotalMilliseconds;
 #if DEBUG_LIMITS

src/Discord.Net.Rest/Net/RateLimitInfo.cs

@@ -11,6 +11,7 @@ namespace Discord.Net
         public int? Remaining { get; }
         public int? RetryAfter { get; }
         public DateTimeOffset? Reset { get; }
+		    public TimeSpan? ResetAfter { get; }
         public TimeSpan? Lag { get; }
 
         internal RateLimitInfo(Dictionary<string, string> headers)
@@ -25,6 +26,8 @@ namespace Discord.Net
                 double.TryParse(temp, NumberStyles.AllowDecimalPoint, CultureInfo.InvariantCulture, out var reset) ? DateTimeOffset.FromUnixTimeMilliseconds((long)(reset * 1000)) : (DateTimeOffset?)null;
             RetryAfter = headers.TryGetValue("Retry-After", out temp) &&
                 int.TryParse(temp, NumberStyles.None, CultureInfo.InvariantCulture, out var retryAfter) ? retryAfter : (int?)null;
+			      ResetAfter = headers.TryGetValue("X-RateLimit-Reset-After", out temp) && 
+				        float.TryParse(temp, out var resetAfter) ? TimeSpan.FromMilliseconds((long)(resetAfter * 1000)) : (TimeSpan?)null;
             Lag = headers.TryGetValue("Date", out temp) &&
                 DateTimeOffset.TryParse(temp, CultureInfo.InvariantCulture, DateTimeStyles.None, out var date) ? DateTimeOffset.UtcNow - date : (TimeSpan?)null;
         }

src/Discord.Net.WebSocket/BaseSocketClient.cs

@@ -81,7 +81,8 @@ namespace Discord.WebSocket
             : base(config, client) => BaseConfig = config;
         private static DiscordSocketApiClient CreateApiClient(DiscordSocketConfig config)
             => new DiscordSocketApiClient(config.RestClientProvider, config.WebSocketProvider, DiscordRestConfig.UserAgent,
-                rateLimitPrecision: config.RateLimitPrecision);
+                rateLimitPrecision: config.RateLimitPrecision,
+				useSystemClock: config.UseSystemClock);
 
         /// <summary>
         ///     Gets a Discord application information for the logged-in user.

src/Discord.Net.WebSocket/DiscordSocketApiClient.cs

@@ -39,8 +39,9 @@ namespace Discord.API
 
         public DiscordSocketApiClient(RestClientProvider restClientProvider, WebSocketProvider webSocketProvider, string userAgent,
             string url = null, RetryMode defaultRetryMode = RetryMode.AlwaysRetry, JsonSerializer serializer = null,
-            RateLimitPrecision rateLimitPrecision = RateLimitPrecision.Second)
-            : base(restClientProvider, userAgent, defaultRetryMode, serializer, rateLimitPrecision)
+            RateLimitPrecision rateLimitPrecision = RateLimitPrecision.Second,
+			bool useSystemClock = true)
+            : base(restClientProvider, userAgent, defaultRetryMode, serializer, rateLimitPrecision, useSystemClock)
         {
             _gatewayUrl = url;
             if (url != null)