Using Optional<T> now.

src/Discord.Net/API/DiscordSocketApiClient.cs

@@ -191,8 +191,9 @@ namespace Discord.API
                 Properties = props,
                 LargeThreshold = largeThreshold,
                 UseCompression = useCompression,
-                ShardingParams = totalShards > 1 ? new int[] { shardID, totalShards } : null
             };
+            if (totalShards > 1)
+                msg.ShardingParams = new int[] { shardID, totalShards };
 
             await SendGatewayAsync(GatewayOpCode.Identify, msg, options: options).ConfigureAwait(false);
         }

src/Discord.Net/API/Gateway/IdentifyParams.cs

@@ -14,7 +14,7 @@ namespace Discord.API.Gateway
         public int LargeThreshold { get; set; }
         [JsonProperty("compress")]
         public bool UseCompression { get; set; }
-        [JsonProperty("shard", NullValueHandling = NullValueHandling.Ignore)]
-        public int[] ShardingParams { get; set; }
+        [JsonProperty("shard")]
+        public Optional<int[]> ShardingParams { get; set; }
     }
 }