feat: adding struct to sync a prefab over network using its hash

Assets/Mirage/Runtime/SyncPrefab.cs

@@ -0,0 +1,83 @@
+using System.Collections.Generic;
+using Mirage.Serialization;
+
+namespace Mirage
+{
+    public struct SyncPrefab
+    {
+        public NetworkIdentity Prefab;
+        public int PrefabHash;
+
+        public SyncPrefab(NetworkIdentity prefab) : this()
+        {
+            Prefab = prefab;
+        }
+
+        public SyncPrefab(int hash) : this()
+        {
+            PrefabHash = hash;
+        }
+
+        /// <summary>
+        /// Searches ClientObjectManager to find a prefab using its hash
+        /// </summary>
+        /// <param name="manager"></param>
+        /// <returns></returns>
+        public NetworkIdentity FindPrefab(ClientObjectManager manager)
+        {
+            if (Prefab == null && PrefabHash != 0)
+            {
+                var handler = manager.GetSpawnHandler(PrefabHash);
+                Prefab = handler.Prefab;
+            }
+            return Prefab;
+        }
+
+        /// <summary>
+        /// Searches ClientObjectManager to find a prefab using its hash
+        /// </summary>
+        /// <param name="manager"></param>
+        /// <returns></returns>
+        public NetworkIdentity FindPrefab(IEnumerable<NetworkIdentity> collection)
+        {
+            if (Prefab == null && PrefabHash != 0)
+            {
+                foreach (var item in collection)
+                {
+                    if (item.PrefabHash == PrefabHash)
+                    {
+                        Prefab = item;
+                        break;
+                    }
+                }
+            }
+            return Prefab;
+        }
+    }
+
+    public static class SyncPrefabSerialize
+    {
+        public static void WriteSyncPrefab(this NetworkWriter writer, SyncPrefab value)
+        {
+            if (value.PrefabHash == 0)
+                value.PrefabHash = GetPrefabHash(value);
+
+            writer.WriteInt32(value.PrefabHash);
+        }
+
+        private static int GetPrefabHash(SyncPrefab value)
+        {
+            var prefab = value.Prefab;
+            if (prefab == null)
+                return 0;
+
+            return prefab.PrefabHash;
+        }
+
+        public static SyncPrefab ReadSyncPrefab(this NetworkReader reader)
+        {
+            var hash = reader.ReadInt32();
+            return new SyncPrefab(hash);
+        }
+    }
+}