OptionalColorOptionalFontOptionalFontOptionalFontOptionalFromOptionalFromOptionalHOptionalHtmlOptionalLabelOptionalMarkdownOptionalNameOptionalPointsOptionalRotationOptionalShapeOptionalStrokeOptionalSubOptionalTagRe-tag the item (see WhiteboardItemBase.Tag); '' clears it.
OptionalTextOptionalTintOptionalTitleOptionalToOptionalToOptionalUrlOptionalWOptionalXOptionalY
Patchable fields for WhiteboardState.UpdateItem (kind/identity fields excluded).