code: function(cb) {
        //console.log('tx running for ' + scope);
        // me.not_ready_ = true;
        // transaction should be active now
        var tx = me.mu_tx_.getTx();
        me.r_no_++;
        req.setTx(tx, me.getLabel() + 'R' + me.r_no_);
      }
docs: create a new transaction and close for invoke in non-transaction context
  @param {Function} cb callback to process tx.