Only creating expensive log message if DEBUG log level is really enabled

fints4k/src/main/kotlin/net/dankito/fints/FinTsClient.kt

@@ -633,7 +633,9 @@ open class FinTsClient @JvmOverloads constructor(
         val prettyPrintMessageWithoutSensitiveData = removeSensitiveDataFromMessage(prettyPrintMessage, dialogContext)
 
 
+        if (log.isDebugEnabled) {
             log.debug("${if (type == MessageLogEntryType.Sent) "Sending" else "Received"} message:\n$prettyPrintMessage")
+        }
 
         messageLogField.add(MessageLogEntry(prettyPrintMessageWithoutSensitiveData, timeStamp, dialogContext.customer))
     }