log/filehandler.go
func (h *TimeRotatingFileHandler) Write(b []byte) (n int, err error) {
	h.doRollover()
	return h.fd.Write(b)
}
func (h *TimeRotatingFileHandler) Write(b []byte) (n int, err error) {
	h.doRollover()
	return h.fd.Write(b)
}
// Write implements Handler interface