title: Deleting memory allocated by repeated fields
body: <p>I  currently have something like this in my proto file:</p>
  
  <pre><code>message MsgA
  {
  required string symbol = 1 ;
  optional int32  freq = 2   [default = 0]; 
  }
  
  message MsgB
  {
  repeated MsgA val = 1 ;
  }
  </code></pre>
  
  <p>Now I know that in order to use the repeated field in <code>MsgB</code>. I need to do something like this: </p>
  
  <pre><code>MsgB inst;
  MsgA some_val = Get_MsgA_Result();
  MsgA* res = inst.add_val();
  *res = some_val;
  </code></pre>
  
  <p>Now my question is once we are done with MsgB how do we reclaim the memory allocated by <code>inst.add_val();</code> ?</p>