title: Protobuf: is there a way to define and use flaggable enumerators?
body: <p>C# has the possibilities for flaggable enumerators. This is very handy to e.g. options:</p>
  
  <pre><code>[Flags]
  public enum Options 
  {
      None    = 0,
      Option1 = 1,
      Option2 = 2,
      Option3 = 4,
      Option4 = 8
  }
  </code></pre>
  
  <p>In Protobuf it is possible to assign custom values to the enumerator values but is lacking (as fas as I know) some attribute to mark the enum as flaggable.</p>
  
  <p>Does anybody know a trick to get flaggable enums in Protobuf?</p>