Check if a Streamer is Live (optional PHP)

My main problem is that I understand the doc in the most parts but I dont know how tow converte this information:

curl -H 'Client-ID: uo6dggojyb8d6soh92zknwmi5ej1q2' \
-X GET 'https://api.twitch.tv/helix/streams?user_login=foo'

to php code.

Thats what I have done yet:

<?php $ClientID = array('Client-ID: uo6dggojyb8d6soh92zknwmi5ej1q2'); $ch = curl_init(); curl_setopt($ch, CURLOPT_HTTPHEADER, $ClientID); curl_setopt($ch, CURLOPT_URL, "https://api.twitch.tv/helix/streams?user_login=foo"); curl_close($ch); ?>

In my console there is only one message with:

{“error”:“Bad Request”,“status”:400,“message”:“No client id specified”}