Adds sharding support

src/Discord.Net/API/Client/GatewaySocket/Commands/Identify.cs

@@ -18,5 +18,7 @@ namespace Discord.API.Client.GatewaySocket
         public int LargeThreshold { get; set; }
         [JsonProperty("compress")]
         public bool UseCompression { get; set; }
+        [JsonProperty("shard")]
+        public int[] ShardingParams { get; set; }
     }
 }

src/Discord.Net/DiscordConfig.cs

@@ -47,6 +47,11 @@ namespace Discord
         /// </summary>
         public int LargeThreshold { get; set; } = 250;
 
+        /// <summary> Gets or sets the id for this shard. Must be less than TotalShards. </summary>
+        public int ShardId { get; set; } = 0;
+        /// <summary> Gets or sets the total number of shards for this application. </summary>
+        public int TotalShards { get; set; } = 1;
+
         //Events
 
         /// <summary> Gets or sets a handler for all log messages. </summary>
@@ -89,6 +94,9 @@ namespace Discord
         public bool UsePermissionsCache { get; }
         public bool EnablePreUpdateEvents { get; }
 
+        public int ShardId { get; }
+        public int TotalShards { get; }
+
         internal DiscordConfig(DiscordConfigBuilder builder)
         {
             LogLevel = builder.LogLevel;
@@ -106,6 +114,8 @@ namespace Discord
             MessageCacheSize = builder.MessageCacheSize;
             UsePermissionsCache = builder.UsePermissionsCache;
             EnablePreUpdateEvents = builder.EnablePreUpdateEvents;
+            ShardId = builder.ShardId;
+            TotalShards = builder.TotalShards;
         }
 
         private static string GetUserAgent(DiscordConfigBuilder builder)

src/Discord.Net/Net/Rest/RestClient.cs

@@ -51,6 +51,9 @@ namespace Discord.Net.Rest
             }
         }
 
+        public int ShardId => _config.ShardId;
+        public int TotalShards => _config.TotalShards;
+
         protected RestClient(DiscordConfig config, string baseUrl, ILogger logger = null)
 		{
 			_config = config;

src/Discord.Net/Net/WebSockets/GatewaySocket.cs

@@ -50,7 +50,7 @@ namespace Discord.Net.WebSockets
             Host = url;
             await BeginConnect(parentCancelToken).ConfigureAwait(false);
             if (SessionId == null)
-                SendIdentify(_rest.Token);
+                SendIdentify(_rest.Token, _rest.ShardId, _rest.TotalShards);
             else
                 SendResume();
         }
@@ -148,7 +148,7 @@ namespace Discord.Net.WebSockets
 			}
 		}
 
-        public void SendIdentify(string token)
+        public void SendIdentify(string token, int shardId = 0, int totalShards = 1)
         {
             var props = new Dictionary<string, string>
             {
@@ -159,9 +159,11 @@ namespace Discord.Net.WebSockets
                 Token = token,
                 Properties = props, 
                 LargeThreshold = _config.LargeThreshold,
-                UseCompression = true
+                UseCompression = true,
+                ShardingParams = new int[] { shardId, totalShards },
             };
-			QueueMessage(msg);
+
+            QueueMessage(msg);
 		}
 
         public void SendResume()