title: Defining a MAC address using protocol buffers
body: <p>I am trying to define an eight byte MAC address data element using protocol buffers in C.  I have tried:</p>
  
  <pre><code>message mac {
      required bytes address = 1 [(nanopb).max_size = 8];
  }
  </code></pre>
  
  <p>but this creates a structure with a size field and an eight byte address field.  I would like just and eight byte address field.</p>
  
  <p>I rejected using a fixed64 element as a MAC address is a sequence of bytes.  Sorry if this is a simple question as I am fairly new to protocol buffers.</p>