How do I append an HTTP header in this format in PHP (cURL)? : <p>I am trying to make a GET request in PHP using cURL and here is what the documentation says about my header:</p>

<blockquote>
  <p>Append an HTTP header called zuluapi using the created signature.</p>
  
  <p><code>zuluapi &lt;publicKey&gt;:&lt;base 64 encoded signature&gt;</code></p>
</blockquote>

<p>I have the publicKey and signature, I just can't seem to figure out how to attach the header in the way they want. When I try to add the header, like below, I get bad header error.</p>

<pre><code>$headers = [
    "zuluapi {$public}:{$signedMessage}"
]; 
</code></pre>
