title: AWS PHP getIterator doesn't work - returns empty results
body: <p>Should be simple code. I have AWS SDK PHP v3 and I created code like this:</p>
  
  <pre><code>require 'aws/aws-autoloader.php';
  
  use Aws\S3\S3Client;
  
  $s3Client = new S3Client([
      'version' =&gt; 'latest',
      'region' =&gt; 'eu-west-1',
      'credentials' =&gt; [
          'key' =&gt; "accesskey",
          'secret' =&gt; "secretkey",
      ],
  ]);
  
  print_r($result = $s3Client-&gt;listBuckets())
  </code></pre>
  
  <p>Now I see my buckets list, but when I tried get <code>ObjectList</code> <code>getIterator</code> like this:</p>
  
  <pre><code>$objects = $s3Client-&gt;getIterator('ListObjects', array(
      'Bucket' =&gt; "bucket")
  );
  
  var_dump($objects);
  </code></pre>
  
  <p>I see: <strong>object(Generator)#95 (0) { }</strong></p>
  
  <p>I am struggling with this second day and I can't find solution? 
  Anyone knows what I do wrong?</p>