let $inp = document.getElementById('app-file-input');
let $file = $inp.files[0];
let $fd = new FormData();
$fd.append('attach', $file);
...
let $xhr = new XMLHttpRequest();
$xhr.addEventListener('load', upload_callback);
$xhr.addEventListener('timeout', upload_callback);
$xhr.addEventListener('error', upload_callback);
$xhr.addEventListener('abort', upload_callback);
$xhr.upload.addEventListener('progress', upload_callback);
$xhr.upload.addEventListener('timeout', upload_callback);
$xhr.upload.addEventListener('error', upload_callback);
$xhr.upload.addEventListener('abort', upload_callback);
$xhr.timeout = 120*1000;
...
$xhr.open('POST', '/upload', true);
$xhr.send($fd);

request body exceeds maximum size (131072) for SSL buffer
could not buffer message body to allow SSL renegotiation to proceed