Add an entity to this world.

Add a system to this world.

Returns the Observable for entities added with the specified components. The Observable is also emitted when a component is added to an entity causing it match the specified component names. Note: make sure to unsubscribe. If needed, use DisposeBag util

Returns the Observable for entities removed with the specified components. The Observable is also emitted when a component is removed from an entity causing it to no longer match the specified component names. Note: make sure to unsubscribe. If needed, use DisposeBag util

Get the entities having all the specified components.

Removes all entities

Remove all systems from this world

Remove and entity from this world.

Remove a system from this world.

For each system in the world, call its update method.