Why telegram bot sends the file twice?

Question

I am sending a file via telegram bot api, I am sure that my code works once, but two files always come! I cannot understand what is the reason, here is my code:

$url = "https://api.telegram.org/bot<Token>/sendDocument?chat_id=<chatId>&caption=Yourfile";
$document = new CURLFile('test.txt');
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, ["document" => $document]);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["Content-Type:multipart/form-data"]);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
$out = curl_exec($ch);
$err = curl_error($ch);
curl_close($ch);
exit('File send');