title: Go Struct / Tag Syntax
body: <p>I'm looking for an explanation of the below syntax:</p>
  <pre><code>type GetBucketTaggingInput struct {
      _ struct{} `locationName:&quot;GetBucketTaggingRequest&quot; type:&quot;structure&quot;`
  
      // The name of the bucket for which to get the tagging information.
      //
      // Bucket is a required field
      Bucket *string `location:&quot;uri&quot; locationName:&quot;Bucket&quot; type:&quot;string&quot; required:&quot;true&quot;`
  }
  </code></pre>
  <p>Specifically, this line:</p>
  <pre><code>_ struct{} `locationName:&quot;GetBucketTaggingRequest&quot; type:&quot;structure&quot;`
  </code></pre>
  <p>I understand the tags are metadata but how is the metadata used in this context?
  Also, I don't understand:</p>
  <pre><code>_ struct{}
  </code></pre>
  <p>Regarding the Bucket variable, again, I'm unsure of the need for the metadata apart maybe from the required field.</p>
  <p>Incidentally, this is from the AWS Go SDK.</p>
  <p>Thanks!</p>