Debug level logging.

DPanic will panic in development and log error message at production env.

Err log a error message with error.

Error level logging.

Fatal level message and call `os.Exit(1)`.

Info level logging.

Infoln log as info level with fmt.Sprintln.

Named create a named logger.

Panic will log at panic level then panic.

Std return a stdlib logger with zap logger underlying.

Warn level logging.