PDF.js version: 3.5.141

These two properties should be marked as not mandatory as they are initialized if not present
}
              }
            );
            if (pageNum % PagesCountLimit.PAUSE_EAGER_PAGE_INIT === 0) {
              await promise;
            }
          }
        });
        this.eventBus.dispatch("pagesinit", { source: this });
        pdfDocument.getMetadata().then(({ info }) => {
          if (pdfDocument !== this.pdfDocument) {
            return; 
          }
          if (info.Language) {
            this.viewer.lang = info.Language;
          }
        });
        if (this.defaultRenderingQueue) {
          this.update();
        }
      })
      .catch(reason => {
        console.error("Unable to initialize viewer", reason);
        this._pagesCapability.reject(reason);
      });
  }
  /**
   * @param {Array|null} labels
   */
  setPageLabels(labels) {