Add WriteSubMessage helper

src/DedicatedServer.cpp

@@ -261,7 +261,7 @@ namespace Feather
             chunkData.Write<int32_t>(biomes[i]);
 
         sections.Finalize();
-        chunkData.WriteData(sections.GetData(), sections.GetDataSize());
+        chunkData.WriteSubMessage(sections);
 
         // Block Ents
         chunkData.WriteVarInt(0);

src/NetworkMessage.h

@@ -77,6 +77,11 @@ namespace Feather
             Write<int64_t>(pos.Encode());
         }
 
+        inline void WriteSubMessage(const NetworkMessage& message)
+        {
+            WriteData(message.GetData(), message.GetDataSize());
+        }
+
         inline void Finalize()
         {
             PrependVarIntSize();