Re-organize in-memory character profile storage.

Now uses a dictionary of int -> profile instead of an array filled with nulls.

Content.Shared/Network/NetMessages/MsgUpdateCharacter.cs

@@ -0,0 +1,50 @@
+using System.IO;
+using Content.Shared.Preferences;
+using Lidgren.Network;
+using Robust.Shared.Interfaces.Network;
+using Robust.Shared.Interfaces.Serialization;
+using Robust.Shared.IoC;
+using Robust.Shared.Network;
+
+namespace Content.Shared.Network.NetMessages
+{
+    /// <summary>
+    /// The client sends this to update a character profile.
+    /// </summary>
+    public class MsgUpdateCharacter : NetMessage
+    {
+        #region REQUIRED
+
+        public const MsgGroups GROUP = MsgGroups.Command;
+        public const string NAME = nameof(MsgUpdateCharacter);
+
+        public MsgUpdateCharacter(INetChannel channel) : base(NAME, GROUP) { }
+
+        #endregion
+
+        public int Slot;
+        public ICharacterProfile Profile;
+
+        public override void ReadFromBuffer(NetIncomingMessage buffer)
+        {
+            Slot = buffer.ReadInt32();
+            var serializer = IoCManager.Resolve<IRobustSerializer>();
+            var length = buffer.ReadVariableInt32();
+            using var stream = buffer.ReadAsStream(length);
+            Profile = serializer.Deserialize<ICharacterProfile>(stream);
+        }
+
+        public override void WriteToBuffer(NetOutgoingMessage buffer)
+        {
+            buffer.Write(Slot);
+            var serializer = IoCManager.Resolve<IRobustSerializer>();
+            using (var stream = new MemoryStream())
+            {
+                serializer.Serialize(stream, Profile);
+                buffer.WriteVariableInt32((int) stream.Length);
+                stream.TryGetBuffer(out var segment);
+                buffer.Write(segment);
+            }
+        }
+    }
+}