public void start(String fileName, IApimanLogger extraLogger) {
        this.logger = new DoubleLogger(this.logger, extraLogger);
        start(fileName);
    }
Set an additional logger implementation. This could be useful if you are intending to redirect the
logging output somewhere atypical (e.g. into the response body).
manager/api/export-import/src/main/java/io/apiman/manager/api/exportimport/manager/StorageImportDispatcher.java