logger: add NewStdLogger and RedirectStdLogger

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

logger/stdlogger.go

@@ -1,6 +1,7 @@
 package logger
 
 import (
+	"bytes"
 	"log"
 )
 
@@ -14,6 +15,21 @@ func NewStdLogger(l Logger, level Level) *log.Logger {
 }
 
 func (sl *stdLogger) Write(p []byte) (int, error) {
+	p = bytes.TrimSpace(p)
 	sl.l.Log(sl.l.Options().Context, sl.level, string(p))
 	return len(p), nil
 }
+
+func RedirectStdLogger(l Logger, level Level) func() {
+	flags := log.Flags()
+	prefix := log.Prefix()
+	writer := log.Writer()
+	log.SetFlags(0)
+	log.SetPrefix("")
+	log.SetOutput(&stdLogger{l: l, level: level})
+	return func() {
+		log.SetFlags(flags)
+		log.SetPrefix(prefix)
+		log.SetOutput(writer)
+	}
+}