Optional
idOptional ID for the Viewer, generated automatically by the Viewer constructor if omitted.
Optional
viewsParamaters to create or configure Views within the target Viewer.
When the ViewerParsms is passed to Viewer.fromParams, for each ViewParams that matches the ID of a pre-existing View, the View is updated with whatever properties are provided on the ViewParams.
For each ViewParams whose ID matches no existiong View, a new View is created, giving it the ID and whatever configurations are provided on the ViewParams.
Parameters for a Viewer.