Integrate IsFragmented into PacketHandler (#532)

IsFragmented doesn't mean anything on its own, i.e. it's almost
certainly a mistake to use it without an accompanying PacketHandler
attribute. It makes more sense to just add it as a field to
PacketHandler.

Co-authored-by: Meru <notfood@users.noreply.github.com>

Author: mibac138

Source/Client/Networking/State/ClientJoiningState.cs

@@ -77,8 +77,7 @@ public void HandleUsernameOk(ByteReader data)
             connection.SendFragmented(Packets.Client_JoinData, writer.ToArray());
         }
 
-        [PacketHandler(Packets.Server_JoinData)]
-        [IsFragmented]
+        [PacketHandler(Packets.Server_JoinData, allowFragmented: true)]
         public void HandleJoinData(ByteReader data)
         {
             Multiplayer.session.gameName = data.ReadString();

Source/Client/Networking/State/ClientLoadingState.cs

@@ -28,8 +28,7 @@ public void HandleWorldDataStart(ByteReader data)
         connection.Lenient = false; // Lenient is set while rejoining
     }
 
-    [PacketHandler(Packets.Server_WorldData)]
-    [IsFragmented]
+    [PacketHandler(Packets.Server_WorldData, allowFragmented: true)]
     public void HandleWorldData(ByteReader data)
     {
         Log.Message("Game data size: " + data.Length);

Source/Client/Networking/State/ClientPlayingState.cs

@@ -208,8 +208,7 @@ public void HandleNotification(ByteReader data)
             Messages.Message(key.Translate(Array.ConvertAll(args, s => (NamedArgument)s)), MessageTypeDefOf.SilentInput, false);
         }
 
-        [PacketHandler(Packets.Server_SyncInfo)]
-        [IsFragmented]
+        [PacketHandler(Packets.Server_SyncInfo, allowFragmented: true)]
         public void HandleDesyncCheck(ByteReader data)
         {
             Multiplayer.game?.sync.AddClientOpinionAndCheckDesync(ClientSyncOpinion.Deserialize(data));
@@ -225,8 +224,7 @@ public void HandleFreze(ByteReader data)
             TickPatch.frozenAt = frozenAt;
         }
 
-        [PacketHandler(Packets.Server_Traces)]
-        [IsFragmented]
+        [PacketHandler(Packets.Server_Traces, allowFragmented: true)]
         public void HandleTraces(ByteReader data)
         {
             var type = (TracesPacket)data.ReadInt32();

Source/Common/Networking/MpConnectionState.cs

@@ -40,11 +40,12 @@ public static void SetImplementation(ConnectionStateEnum state, Type type)
 
                 if (method.GetParameters().Length != 1 || method.GetParameters()[0].ParameterType != typeof(ByteReader))
                     throw new Exception($"Bad packet handler signature for {method}");
+
                 if (packetHandlers[(int)state, (int)attr.packet] != null)
-                    throw new Exception($"Packet {state}:{attr.packet} already has a handler");
-                bool fragment = method.GetAttribute<IsFragmentedAttribute>() != null;
+                    throw new Exception($"Packet {state}:{type} already has a handler");
+
                 packetHandlers[(int)state, (int)attr.packet] =
-                    new PacketHandlerInfo(MethodInvoker.GetHandler(method), fragment);
+                    new PacketHandlerInfo(MethodInvoker.GetHandler(method), attr.allowFragmented);
             }
         }
     }

Source/Common/Networking/PacketHandlerAttribute.cs

@@ -5,18 +5,10 @@
 namespace Multiplayer.Common
 {
     [MeansImplicitUse]
-    public class PacketHandlerAttribute : Attribute
-    {
-        public readonly Packets packet;
-
-        public PacketHandlerAttribute(Packets packet)
-        {
-            this.packet = packet;
-        }
-    }
-
-    public class IsFragmentedAttribute : Attribute
+    public class PacketHandlerAttribute(Packets packet, bool allowFragmented = false) : Attribute
     {
+        public readonly Packets packet = packet;
+        public readonly bool allowFragmented = allowFragmented;
     }
 
     public record PacketHandlerInfo(FastInvokeHandler Method, bool Fragment);

Source/Common/Networking/State/ServerPlayingState.cs

@@ -28,8 +28,7 @@ public void HandleDesynced(ByteReader data)
             Server.playerManager.OnDesync(Player, tick, diffAt);
         }
 
-        [PacketHandler(Packets.Client_Traces)]
-        [IsFragmented]
+        [PacketHandler(Packets.Client_Traces, allowFragmented: true)]
         public void HandleTraces(ByteReader data)
         {
             var type = (TracesPacket)data.ReadInt32();
@@ -77,8 +76,7 @@ public void HandleChat(ByteReader data)
             }
         }
 
-        [PacketHandler(Packets.Client_WorldDataUpload)]
-        [IsFragmented]
+        [PacketHandler(Packets.Client_WorldDataUpload, allowFragmented: true)]
         public void HandleWorldDataUpload(ByteReader data)
         {
             if (Server.ArbiterPlaying ? !Player.IsArbiter : !Player.IsHost) // policy
@@ -203,8 +201,7 @@ public void HandleClientKeepAlive(ByteReader data)
             }
         }
 
-        [PacketHandler(Packets.Client_SyncInfo)]
-        [IsFragmented]
+        [PacketHandler(Packets.Client_SyncInfo, allowFragmented: true)]
         public void HandleDesyncCheck(ByteReader data)
         {
             var arbiter = Server.ArbiterPlaying;