/// <summary>
/// Initializes a new instance of the <see cref="EntityManager" /> class.
/// </summary>
/// <param name="entityWorld">The entity world.</param>
public EntityManager(EntityWorld entityWorld)
{
Debug.Assert(entityWorld != null, "EntityWorld must not be null.");
this.uniqueIdToEntities = new Dictionary <int, Entity>();
this.removedAndAvailable = new Bag <Entity>();
this.componentsByType = new Bag <Bag <IEntityComponent> >();
this.ActiveEntities = new Bag <Entity>();
this.identifierPool = new Bag <int>(4);
this.RemovedEntitiesRetention = 100;
this.entityWorld = entityWorld;
RemovedComponentEvent += EntityManagerRemovedComponentEvent;
}