Added RetryAfter property for ratelimit errors, added parsing of rate limit return

CryptoExchange.Net/Objects/Error.cs

@@ -1,4 +1,6 @@
-namespace CryptoExchange.Net.Objects
+using System;
+
+namespace CryptoExchange.Net.Objects
 {
     /// <summary>
     /// Base class for errors
@@ -202,15 +204,14 @@
     }
 
     /// <summary>
-    /// Rate limit exceeded
+    /// Rate limit exceeded (client side)
     /// </summary>
-    public class RateLimitError : Error
+    public abstract class BaseRateLimitError : Error
     {
         /// <summary>
-        /// ctor
+        /// When the request can be retried
         /// </summary>
-        /// <param name="message"></param>
-        public RateLimitError(string message) : base(null, "Rate limit exceeded: " + message, null) { }
+        public DateTime? RetryAfter { get; set; }
 
         /// <summary>
         /// ctor
@@ -218,7 +219,47 @@
         /// <param name="code"></param>
         /// <param name="message"></param>
         /// <param name="data"></param>
-        protected RateLimitError(int? code, string message, object? data): base(code, message, data) { }
+        protected BaseRateLimitError(int? code, string message, object? data) : base(code, message, data) { }
+    }
+
+    /// <summary>
+    /// Rate limit exceeded (client side)
+    /// </summary>
+    public class ClientRateLimitError : BaseRateLimitError
+    {
+        /// <summary>
+        /// ctor
+        /// </summary>
+        /// <param name="message"></param>
+        public ClientRateLimitError(string message) : base(null, "Client rate limit exceeded: " + message, null) { }
+
+        /// <summary>
+        /// ctor
+        /// </summary>
+        /// <param name="code"></param>
+        /// <param name="message"></param>
+        /// <param name="data"></param>
+        protected ClientRateLimitError(int? code, string message, object? data): base(code, message, data) { }
+    }
+
+    /// <summary>
+    /// Rate limit exceeded (server side)
+    /// </summary>
+    public class ServerRateLimitError : BaseRateLimitError
+    {
+        /// <summary>
+        /// ctor
+        /// </summary>
+        /// <param name="message"></param>
+        public ServerRateLimitError(string message) : base(null, "Server rate limit exceeded: " + message, null) { }
+
+        /// <summary>
+        /// ctor
+        /// </summary>
+        /// <param name="code"></param>
+        /// <param name="message"></param>
+        /// <param name="data"></param>
+        protected ServerRateLimitError(int? code, string message, object? data) : base(code, message, data) { }
     }
 
     /// <summary>

CryptoExchange.Net/Objects/RateLimiter.cs

@@ -256,7 +256,7 @@ namespace CryptoExchange.Net.Objects
                             historyTopic.Semaphore.Release();
                             var msg = $"Request to {endpoint} failed because of rate limit `{historyTopic.Type}`. Current weight: {currentWeight}/{historyTopic.Limit}, request weight: {requestWeight}";
                             logger.Log(LogLevel.Warning, msg);
-                            return new CallResult<int>(new RateLimitError(msg));
+                            return new CallResult<int>(new ClientRateLimitError(msg) { RetryAfter = DateTime.UtcNow.AddSeconds(thisWaitTime) });
                         }
 
                         logger.Log(LogLevel.Information, $"Request to {endpoint} waiting {thisWaitTime}ms for rate limit `{historyTopic.Type}`. Current weight: {currentWeight}/{historyTopic.Limit}, request weight: {requestWeight}");