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)_.
await loadingTask.destroy();
    });
    it("creates pdf doc from URL and aborts before worker initialized", async function () {
      const loadingTask = getDocument(basicApiGetDocumentParams);
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      const destroyed = loadingTask.destroy();
      try {
        await loadingTask.promise;
        
        expect(false).toEqual(true);
      
        expect(true).toEqual(true);
        await destroyed;
      }
    });
    it("creates pdf doc from URL and aborts loading after worker initialized", async function () {
      const loadingTask = getDocument(basicApiGetDocumentParams);
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      
      
      const destroyed = loadingTask._worker.promise.then(function () {
        return loadingTask.destroy();
      });
      await destroyed;
      expect(true).toEqual(true);
    });
    it("creates pdf doc from typed array", async function () {
      const typedArrayPdf = await DefaultFileReaderFactory.fetch({
        path: TEST_PDFS_PATH + basicApiFileName,
      });