Is there a way to extend/overload existing FormData append method in Typescript/Angular to be able to provide custom header per file upload? For example to be able to add Content-MD5 per each file:
------WebKitFormBoundary9GAg4rr3232 Content-Disposition: form-data; name="file1"; filename="file" Content-Type: image/png Content-MD5:MD5Hash
------WebKitFormBoundary9GAg4r99999 Content-Disposition: form-data; name="file2"; filename="file2" Content-Type: image/png Content-MD5:MD5Hash