Gets or sets the states of the optional content groups that decide what the render shows, computed from any configuration
of the document (GetStates(PdfOptionalContentConfiguration, PdfOptionalContentState?)); null, the default, for the states
of the default configuration.
public PdfOptionalContentState? OptionalContentState { get; set; }
ISO 32000-2 §8.11.4.3 (configurations) and §8.11.4.5 (the initial states). It decides the page content's optional sections
and XObjects (§8.11.3), the annotations' OC entries (§8.11.3.3) and which alternate image is painted (§8.9.5.4). For
Print the configuration's auto-state entries for the Print event are applied over these states
(§8.11.4.4); see CreateDisplayList(DisplayLayers, DisplayIntent, ContentOptions).