title: How do I represent a UUID in a protobuf message?
body: <p>I want to attach a UUID to a field in my protobuf User message example.</p>
  
  <pre><code>message User {
    // field containing id as UUID type
    required string email;
    optional string name;
  }
  </code></pre>
  
  <p>I know that protobuf messages do not yet support the UUID type. I've read that the best approach is to have a UUID message type.</p>
  
  <p>So I'm guessing my User message would import my UUID message proto definition and use it as a field type like so:</p>
  
  <pre><code>import "myproject/UUID.proto";
  
  message User {
    required UUID id;
    required string email;
    optional string name;
  }
  </code></pre>
  
  <p>My question is, how will the UUID message look like, and how will I encode/decode it? I'm aiming for Java/Scala and C# compatibility.</p>