How to send value to php_curl like console -d?

Question

PHP

I do. request via console in ElasticSearch:
curl -XPOST ' localhost:9200/events/play/_bulk ' -d '
{"metadata": {}}
{"element": 1}'
How to send what is passed after -d in PHP with using the php_curl extension?

$c = curl_init();
$opts = [
CURLOPT_RETURNTRANSFER => true,
CURLOPT_URL => $address,
CURLOPT_BINARYTRANSFER => true,
CURLOPT_POST => true,
// CURLOPT_POSTFIELDS = [], // ???
];
curl_setopt_array($c, $opts);
$res = curl_exec($c);
curl_close($c);

As a matter of fact it is necessary to transfer string with transfers (\n).
Everything works through the console. In PHP, requests are sent, but there are no changes in Elastica.
No need to suggest using exec and elasticsearch driver
Thank you all in advance!

Answer 1

Add

curl_setopt($c, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded'));  
$pf = "{\"metadata\": {}}\n{\"element\": 1}";
curl_setopt($c, CURLOPT_POSTFIELDS, $pf);