function setVerbosityLevel(level) {
  if (Number.isInteger(level)) {
    verbosity = level;
  }
}
Refer to the `WorkerTransport.getRenderingIntent`-method in the API, to see
how these flags are being used:
 - ANY, DISPLAY, and PRINT are the normal rendering intents, note the
   `PDFPageProxy.{render, getOperatorList, getAnnotations}`-methods.
 - SAVE is used, on the worker-thread, when saving modified annotations.
 - ANNOTATIONS_FORMS, ANNOTATIONS_STORAGE, ANNOTATIONS_DISABLE control which
   annotations are rendered onto the canvas (i.e. by being included in the
   operatorList), note the `PDFPageProxy.{render, getOperatorList}`-methods
   and their `annotationMode`-option.
 - IS_EDITING is used when editing is active in the viewer.
 - OPLIST is used with the `PDFPageProxy.getOperatorList`-method, note the
   `OperatorList`-constructor (on the worker-thread).