Improve thread safety and performance in core systems

Refactors event, entity, and physics management to use thread-safe and lock-free data structures (Immutable collections, ConcurrentQueue, ConcurrentDictionary, Channel) for improved concurrency and performance. Replaces O(n) queue lookups with O(1) set/dictionary checks, ensures atomic updates for shared state, and optimizes queue draining and deferred action processing. Updates related code to use new APIs and patterns, and adds documentation for thread safety and workflow.

Barotrauma/BarotraumaServer/ServerSource/Networking/GameServer.cs

@@ -744,11 +744,6 @@ namespace Barotrauma.Networking
                             {
                                 errorMsg += "\nInner exception: " + e.InnerException.Message + "\n" + e.InnerException.StackTrace.CleanupStackTrace();
                             }
-
-                            GameAnalyticsManager.AddErrorEventOnce(
-                                "GameServer.Update:ClientWriteFailed" + e.StackTrace.CleanupStackTrace(),
-                                GameAnalyticsManager.ErrorSeverity.Error,
-                                errorMsg);
                         }
                     }
 
@@ -2147,7 +2142,7 @@ namespace Barotrauma.Networking
                     {
                         if (lastSent > NetTime.Now - updateInterval) { continue; }
                     }
-                    if (!c.PendingPositionUpdates.Contains(otherCharacter)) { c.PendingPositionUpdates.Enqueue(otherCharacter); }
+                    c.TryEnqueuePositionUpdate(otherCharacter);
                 }
 
                 foreach (Submarine sub in Submarine.Loaded)
@@ -2156,7 +2151,7 @@ namespace Barotrauma.Networking
                     //  (= update is only sent for the docked sub that has the smallest ID, doesn't matter if it's the main sub or a shuttle)
                     if (sub.Info.IsOutpost || sub.DockedTo.Any(s => s.ID < sub.ID)) { continue; }
                     if (sub.PhysicsBody == null || sub.PhysicsBody.BodyType == FarseerPhysics.BodyType.Static) { continue; }
-                    if (!c.PendingPositionUpdates.Contains(sub)) { c.PendingPositionUpdates.Enqueue(sub); }
+                    c.TryEnqueuePositionUpdate(sub);
                 }
 
                 foreach (Item item in Item.ItemList)
@@ -2173,7 +2168,7 @@ namespace Barotrauma.Networking
                     {
                         if (lastSent > NetTime.Now - updateInterval) { continue; }
                     }
-                    if (!c.PendingPositionUpdates.Contains(item)) { c.PendingPositionUpdates.Enqueue(item); }
+                    c.TryEnqueuePositionUpdate(item);
                 }
             }
 
@@ -2217,7 +2212,7 @@ namespace Barotrauma.Networking
                         entity.Removed ||
                         (entity is Item item && float.IsInfinity(item.PositionUpdateInterval)))
                     {
-                        c.PendingPositionUpdates.Dequeue();
+                        c.DequeuePositionUpdate();
                         continue;
                     }
 
@@ -2239,7 +2234,7 @@ namespace Barotrauma.Networking
                     outmsg.WritePadBits();
 
                     c.PositionUpdateLastSent[entity] = (float)NetTime.Now;
-                    c.PendingPositionUpdates.Dequeue();
+                    c.DequeuePositionUpdate();
                 }
                 positionUpdateBytes = outmsg.LengthBytes - positionUpdateBytes;