improve interop with other libs/stdlib

logging/funcs_file.go

@@ -223,7 +223,15 @@ func (l *FileLogger) Warning(s string, v ...interface{}) (err error) {
 // ToLogger returns a stdlib log.Logger.
 func (l *FileLogger) ToLogger(prio logPrio) (stdLibLog *log.Logger) {
 
-	stdLibLog = log.New(&logWriter{backend: l, prio: prio}, "", 0)
+	stdLibLog = log.New(l.ToRaw(prio), "", 0)
+
+	return
+}
+
+// ToRaw returns a *logWriter.
+func (l *FileLogger) ToRaw(prio logPrio) (raw *logWriter) {
+
+	raw = &logWriter{backend: l, prio: prio}
 
 	return
 }