mocktracer/mockspan.go
func (s *MockSpan) BaggageItem(key string) string {
	s.RLock()
	defer s.RUnlock()
	return s.SpanContext.Baggage[key]
}
func (s *MockSpan) BaggageItem(key string) string {
	s.RLock()
	defer s.RUnlock()
	return s.SpanContext.Baggage[key]
}
func ( s * MockSpan ) BaggageItem ( key string ) string { s . RLock ( ) defer s . RUnlock ( ) return s . SpanContext . Baggage [ key ] }
// BaggageItem belongs to the Span interface
BaggageItem belongs to the Span interface