The id of this Node. This simple string identifier is useful for
finding a specific Node within the scene graph. While the id of a Node
should be unique within the scene graph, this uniqueness is not enforced.
This is analogous to the "id" attribute on an HTML element
(CSS ID Specification).
Node using the setId
method or null, if no id has been assigned.
CSS Reference Guide
@defaultValue null
Diagram: Node