src/vs/workbench/api/common/extHostDocumentData.ts/ExtHostDocumentData/dispose
class ExtHostDocumentData:	override dispose(): void {
		// we don't really dispose documents but let
		// extensions still read from them. some
		// operations, live saving, will now error tho
		ok(!this._isDisposed);
		this._isDisposed = true;
		this._isDirty = false;
	}