func (l *DefLog) Errorf(format string, args ...interface{}) {
	l.logf(log.ERROR, format, args...)
}
Errorf calls go 'log.Output' and can be used for logging errors.
Arguments are handled in the manner of fmt.Printf.
package modlog
import (
	"fmt"
	"io"
	builtinlog "log"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"github.com/hyperledger/aries-framework-go/pkg/internal/common/logging/metadata"
	"github.com/hyperledger/aries-framework-go/spi/log"
)
const (
	logLevelFormatter   = "UTC %s-> %s "
	logPrefixFormatter  = " [%s] "
	callerInfoFormatter = "- %s "
)
func NewDefLog(module string) *DefLog {
	logger := builtinlog.New(os.Stdout, fmt.Sprintf(logPrefixFormatter, module),
		builtinlog.Ldate|builtinlog.Ltime|builtinlog.LUTC)
	return &DefLog{logger: logger, module: module}
}
type DefLog struct {
	logger *builtinlog.Logger
	module string
}
func (l *DefLog) Fatalf(format string, args ...interface{}) {
	l.logf(log.CRITICAL, format, args...)
	os.Exit(1)
}
func (l *DefLog) Panicf(format string, args ...interface{}) {
	l.logf(log.CRITICAL, format, args...)
	panic(fmt.Sprintf(format, args...))
}
func (l *DefLog) Debugf(format string, args ...interface{}) {
	l.logf(log.DEBUG, format, args...)
}
func (l *DefLog) Infof(format string, args ...interface{}) {
	l.logf(log.INFO, format, args...)
}
func (l *DefLog) Warnf(format string, args ...interface{}) {
	l.logf(log.WARNING, format, args...)
}