code: public void commandComplete(ImapCommand command, String responseCode) {
          tag();
          message(OK);
          responseCode(responseCode);
          commandName(command);
          message("completed.");
          end();
      }
docs: Writes a standard tagged OK response on completion of a command,
  with a response code (eg READ-WRITE)
  Response is writen as:
  <pre>     a01 OK [responseCode] COMMAND_NAME completed.</pre>
  
  @param command      The ImapCommand which was completed.
  @param responseCode A string response code to send to the client.