tx.go
func NewTx(name string) *tx {
	return &tx{
		Tracer:   &NRTxTracer{},
		Reporter: &NRTxReporter{},
		name:     name,
		txnType:  WebTransaction,
		ss:       NewSegmentStack(),
		mtx:      &sync.Mutex{},
	}
}
func NewTx(name string) *tx {
	return &tx{
		Tracer:   &NRTxTracer{},
		Reporter: &NRTxReporter{},
		name:     name,
		txnType:  WebTransaction,
		ss:       NewSegmentStack(),
		mtx:      &sync.Mutex{},
	}
}
// NewTx returns a new transaction.