rename Preallocate to PreallocateEntitySlots

Svelto.ECS/EnginesRootEntities.cs

@@ -331,7 +331,7 @@ namespace Svelto.ECS
                 _weakEngine.Target.BuildEntityInGroup(entityID, groupID, entityDescriptor, implementors);
             }
 
-            public void Preallocate<T>(int size) where T : IEntityDescriptor, new()
+            public void PreallocateEntitySlots<T>(int size) where T : IEntityDescriptor, new()
             {
                 _weakEngine.Target.Preallocate<T>(size);
             }

Svelto.ECS/IEnginesInterfaces.cs

@@ -2,7 +2,7 @@ namespace Svelto.ECS
 {   
     public interface IEntityFactory
     {
-        void Preallocate<T>(int size) where T : IEntityDescriptor, new();
+        void PreallocateEntitySlots<T>(int size) where T : IEntityDescriptor, new();
 
         void BuildEntity<T>(int entityID, object[] implementors) where T:IEntityDescriptor, new();
         void BuildEntity(int entityID, IEntityDescriptorInfo entityDescriptorInfo, object[] implementors);