EntityEvent fixes:

- Clients wait for midround syncing to finish before applying the remote state to connection panels and inventories (because the wires connected to the connection panel or items in the inventory may not exist before the EntitySpawner events have been received).
- Server writes 0 as the projectile ID if the projectile doesn't exist anymore when a Turret event is sent.
- More info in networkevent error messages.

Barotrauma/BarotraumaClient/Source/Items/Components/Signal/ConnectionPanel.cs

@@ -1,5 +1,9 @@
 using Barotrauma.Networking;
+using Lidgren.Network;
 using Microsoft.Xna.Framework.Graphics;
+using System;
+using System.Collections.Generic;
+using System.Linq;
 
 namespace Barotrauma.Items.Components
 {
@@ -24,5 +28,66 @@ namespace Barotrauma.Items.Components
             HighlightedWire = null;
             Connection.DrawConnections(spriteBatch, this, character);
         }
+
+
+        public void ClientRead(ServerNetObject type, NetBuffer msg, float sendingTime)
+        {
+            if (GameMain.Client.MidRoundSyncing)
+            {
+                //delay reading the state until midround syncing is done
+                //because some of the wires connected to the panel may not exist yet
+                int bitsToRead = Connections.Count * Connection.MaxLinked * 16;
+                StartDelayedCorrection(type, msg.ExtractBits(bitsToRead), sendingTime, waitForMidRoundSync: true);
+            }
+            else
+            {
+                ApplyRemoteState(msg);
+            }
+        }
+
+        private void ApplyRemoteState(NetBuffer msg)
+        {
+            List<Wire> prevWires = Connections.SelectMany(c => Array.FindAll(c.Wires, w => w != null)).ToList();
+            List<Wire> newWires = new List<Wire>();
+
+            foreach (Connection connection in Connections)
+            {
+                connection.ClearConnections();
+            }
+
+            foreach (Connection connection in Connections)
+            {
+                for (int i = 0; i < Connection.MaxLinked; i++)
+                {
+                    ushort wireId = msg.ReadUInt16();
+
+                    Item wireItem = Entity.FindEntityByID(wireId) as Item;
+                    if (wireItem == null) continue;
+
+                    Wire wireComponent = wireItem.GetComponent<Wire>();
+                    if (wireComponent == null) continue;
+
+                    newWires.Add(wireComponent);
+
+                    connection.Wires[i] = wireComponent;
+                    wireComponent.Connect(connection, false);
+                }
+            }
+
+            foreach (Wire wire in prevWires)
+            {
+                if (wire.Connections[0] == null && wire.Connections[1] == null)
+                {
+                    wire.Item.Drop(null);
+                }
+                //wires that are not in anyone's inventory (i.e. not currently being rewired) can never be connected to only one connection
+                // -> someone must have dropped the wire from the connection panel
+                else if (wire.Item.ParentInventory == null &&
+                    (wire.Connections[0] != null ^ wire.Connections[1] != null))
+                {
+                    wire.Item.Drop(null);
+                }
+            }
+        }
     }
 }