How to POST a large amount of data within PHP curl without memory overhead?

$curl = curl_init();
curl_setopt( $curl, CURLOPT_PUT, 1 );
curl_setopt( $curl, CURLOPT_INFILESIZE, filesize($tmpFile) );
curl_setopt( $curl, CURLOPT_INFILE, ($in=fopen($tmpFile, 'r')) );
curl_setopt( $curl, CURLOPT_CUSTOMREQUEST, 'POST' );
curl_setopt( $curl, CURLOPT_HTTPHEADER, [ 'Content-Type: application/json' ] );
curl_setopt( $curl, CURLOPT_URL, $url );
curl_setopt( $curl, CURLOPT_RETURNTRANSFER, 1 );
$result = curl_exec($curl);
curl_close($curl);
fclose($in);