code: func (s *Logging) Write(b []byte) (int, error) {
  	s.mutex.RLock()
  	w := s.writer
  	s.mutex.RUnlock()
  
  	return w.Write(b)
  }
docs: // Write satisfies the io.Write contract. It delegates to the writer argument
  // of SetWriter or the Writer field of Config. The Core uses this when encoding
  // log records.