https://github.com/mozilla/pdf.js/blob/0df1a5661958df0c4ed2f73b0f3266d825c5c280/src/display/api.js#L710-L719
The return type signature `@returns {Promise<{num: number, gen: number}>}` is mismatched with its definition. (should be `@returns {Promise<number>}`)
{
              length: params.length,
              initialData: params.initialData,
              progressiveDone: params.progressiveDone,
              contentDispositionFilename: params.contentDispositionFilename,
              disableRange: params.disableRange,
              disableStream: params.disableStream,
            },
            rangeTransport
          );
        } else if (!params.data) {
          networkStream = createPDFNetworkStream({
            url: params.url,
            length: params.length,
            httpHeaders: params.httpHeaders,
            withCredentials: params.withCredentials,
            rangeChunkSize: params.rangeChunkSize,
            disableRange: params.disableRange,
            disableStream: params.disableStream,
          });
        }
        resolve(networkStream);
      });
      return Promise.all([workerIdPromise, networkStreamPromise]).then(
        function ([workerId, networkStream]) {
          if (task.destroyed) {
            throw new Error("Loading aborted");
          }
          const messageHandler = new MessageHandler(
            docId,