function upload_computed_data(data, chunksize)

if nargin < 2
    chunksize = 2500;
end

nchunks     = ceil(height(data) / chunksize);
firstchunk  = true;

for n = 1:nchunks
    from    = (n-1) * chunksize + 1;
    to      = min(n * chunksize, height(data));
    
    chunk   = data(from:to, :);
    csvname = [tempname() '.csv'];
    writetable(chunk, csvname);
    gzname  = gzip(csvname);
    delete(csvname);
    
    import matlab.net.http.*
    import matlab.net.http.io.*
    fp  = FileProvider(gzname);
    if firstchunk
        % UGLY INFLEXIBLE HACK
        userdata = data.Properties.UserData;
        userdata{1,3}.duration = milliseconds(userdata{1,3}.duration);
        mfp = MultipartFormProvider('file', fp, 'userdata', StringProvider(jsonencode(userdata)));
    else
        mfp = MultipartFormProvider('file', fp);
    end
    req = RequestMessage('post', HeaderField('Auth', 'Qnb7jfeGZM'), mfp);
    url = 'https://driver-observer.thi.de/upload_computed_data.php';
    if firstchunk
        url         = strcat(url,'?clear=1');
        firstchunk  = false;
    end
    res = req.send(url);
    delete(gzname{1});
    
    if res.StatusCode ~= StatusCode.OK
        throw(MException('upload_computed_data:http_error', ...
            'HTTP Error %s (%s); Body: %s', string(res.StatusCode), ...
            string(getReasonPhrase(res.StatusCode)), res.Body.Data));
    end
end
end