code: func NewSegment(name, traceID, spanID string, conn net.Conn) *Segment {
  	return &Segment{
  		Mutex:      &sync.Mutex{},
  		Name:       name,
  		TraceID:    traceID,
  		ID:         spanID,
  		StartTime:  now(),
  		InProgress: true,
  		conn:       conn,
  	}
  }
docs: // NewSegment creates a new segment that gets written to the given connection
  // on close.