The event is fired before an Entity travels to a dimension.
dimension getter is the id of the dimension the entity is traveling to.
The event is cancelable.
If the event is canceled, the Entity will not travel to the dimension.
The event does not have a result.
It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import at the very top of the file.