anchor.diff:      });
     }
   
  -  executeMessage(MongoMessage message, WriteConcern writeConcern, {_Connection connection}) {
  +  executeMessage(MongoMessage message, WriteConcern writeConcern,
  +      {_Connection connection}) {
       if (state != State.OPEN) {
         throw new MongoDartError('DB is not open. $state');
       }
  
positive.code:     if (writeConcern == null) {
        writeConcern = _writeConcern;
      }
      connection.execute(message,writeConcern == WriteConcern.ERRORS_IGNORED);
    }
  
    Future open({WriteConcern writeConcern: WriteConcern.ACKNOWLEDGED}){
      return new Future.sync(() {
        if (state == State.OPENING) {
          throw new MongoDartError('Attempt to open db in state $state');
  
negative.code:         errMsg = "Error executing Db command, Document length 0 $replyMessage";
          print("Error: $errMsg");
          var m = new Map();
          m["errmsg"] = errMsg;
          result.completeError(m);
        } else if (replyMessage.documents[0]['ok'] == 1.0 &&
            replyMessage.documents[0]['err'] == null) {
          result.complete(replyMessage.documents[0]);
        } else {
          result.completeError(replyMessage.documents[0]);
  