my $ua = WWW::Mechanize->new();
    $ua->credentials('apikey','that_api_key');
    my $r = HTTP::Request->new(
        'POST' => 'https://stream-fra.watsonplatform.net/speech-to-text/api/v1/recognize',
        [
            'Accept' => '*/*',
            'Host' => 'stream-fra.watsonplatform.net:443',
            'User-Agent' => 'curl/7.55.1',
            'Content-Length' => length $file_content,
            'Content-Type' => 'audio/flac',
        ],
        $file_content
    );
    my $res = $ua->request( $r );