title: Message Identifier in Protobug Message
body: <p>Is there a way to get something like an ID for a protobuf message.</p>
  
  <p>E.g. I have:</p>
  
  <pre><code>syntax = "proto3";
  
  package protobuf;
  
  message parameters_t
  {
      string audio_device = 1;
  }
  
  message master_t
  {
      enum type_t
      {
          unknown = 0;
          login_rsp = 1;
      }
  
      type_t type = 1;
  }
  </code></pre>
  
  <p>What I want to do in C++ is send the size over the wire, then some ID of the message and the the buffer.</p>
  
  <p>E.g. <code>paramters_t</code> is ID 0 (statically accessible) and <code>master_t</code> is ID 1, so I can do in my code:</p>
  
  <pre><code>if (id == protobuf::master_t::id) {
      ...
  }
  else if (id == protobuf::paramters_t::id) {
      ...
  }
  </code></pre>
  
  <p>Is there any way to achieve this without manually assigning the values? I want that to be set in the protofile somehow. It can be a constant I define myself, i dont care.</p>