Hello!

Let me know if i should have opened this issue on the [pdfjs-dist](https://github.com/mozilla/pdfjs-dist) repo but I though here would fit.

I'm using pdfjs-dist and I'm in need of some more types to be exported. I have no idea how the types end up in the dist-repo but would love to open a PR if only someone could point me in the right direction 😃 Since I was using an older version of pdfjs-dist I realize the only type I need that's not in the type defs in the latest release are _PageViewport_ from _[display/display_utils](https://github.com/mozilla/pdf.js/blob/master/src/display/display_utils.js#L153)_.
});
    it(
      "should fetch document info and page, without range, " +
        "using complete initialData",
      async function () {
        let fetches = 0;
        const data = await dataPromise;
        const transport = new PDFDataRangeTransport(
          data.length,
          data,
          /* progressiveDone = */ true
        );
        transport.reque (begin, end) {
          fetches++;
        };
        const loadingTask = getDocument({
          disableRange: true,
          range: transport,
        });
        const pdfDocument = await loadingTask.promise;
        expect(pdfDocument.numPages).toEqual(14);
        const pdfPage = await pdfDocument.getPage(10);
        expect(pdfPage.rotate).toEqual(0);
        expect(fetches).toEqual(0);
        await loadingTask.destroy();
      }
    );
  });
});