Send file using wp_safe_remote_post

On my local tests, I’m using the follow code to send a file on HTTP connection:

$url = 'https://...';

$ch = curl_init();

$tmpfile = 'teste.txt';
$curl_file = new CURLFile(realpath($tmpfile),'text/csv',$tmpfile);
$file = array('file[]' => $curl_file);

curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $file); //$data);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$response = curl_exec($ch);
if(curl_error($ch)) {
    echo 'error:' . curl_error($ch);
} else {
    echo $response;
}

This code works perfectly!

Now, I wanna connect to this URL from my WordPress application.

The problem is that I don’t know how to send files using the wp_safe_remote_post.

I tried the following code:

$url = 'https://...';

$tmpfile = WP_CONTENT_DIR . '/test.txt';
$params = array(
    'method'   => 'POST',
    'timeout'  => 60,
    'body'     => [
        'file[]'   => realpath( $tmpfile ),
    ]
);

$response = wp_safe_remote_post( $url, $params );

But the remote server says that no file was sended!

What I did wrong? How to make this work?

Thanks for your help!