code: func (entry *Entry) WithFields(fields lg.Fields) *Entry {
  	data := make(lg.Fields, len(entry.fields)+len(fields))
  	for k, v := range entry.fields {
  		data[k] = v
  	}
  	for k, v := range fields {
  		data[k] = v
  	}
  	return &Entry{logger: entry.logger, fields: data, lgEntry: entry.lgEntry}
  }
docs: // WithFields stores field entries. These entries are used later when log method (Info, Debug, etc) is called