@Override
    public void error(String message, Throwable error) {
        System.err.println("** ERROR: " + message + " **");
        error.printStackTrace(System.err);
    }
@see IApimanLogger#error(java.lang.String, java.lang.Throwable)
common/logging/core/src/main/java/io/apiman/common/logging/impl/SystemOutLogger.java