mocktracer/mockspan.go
func (s *MockSpan) LogEvent(event string) {
	s.LogFields(log.String("event", event))
}
func (s *MockSpan) LogEvent(event string) {
	s.LogFields(log.String("event", event))
}
func ( s * MockSpan ) LogEvent ( event string ) { s . LogFields ( log . String ( " " , event ) ) }
// LogEvent belongs to the Span interface
LogEvent belongs to the Span interface