NG-ZORRO NzUpload How use NzDownload function

Question

<nz-upload
          class="file-uploader"
          [nzCustomRequest]="customReq"
          [(nzFileList)]="fileList"
          [nzDownload]="downloadReq"
          [nzBeforeUpload]="beforeUpload"
          (nzChange)="handleChange($event)"
  >
    <button tc-button [beforeIcon]="'icofont-upload-alt'" [type]="'button'">Click to upload</button>
  </nz-upload>

Typescript

downloadReq = (file: NzUploadFile) => {}

How use this method to request? File can be downloaded who has access. And I can't set header to download request. I use angular 9.

Nz Upload