private static IDelegateFactory resolveLoggerFactory() {
        String sysProp = System.getProperty(APIMAN_LOGGER);
        if (sysProp == null) {
            return ApimanLoggerFactoryRegistry.getDefaultLoggerFactory();
        }
        return ApimanLoggerFactoryRegistry.getLoggerFactory(sysProp);
    }
If system property is set, resolve the factory of that name, otherwise use the default logger.

<p>In future we could use a more intelligent approach that attempts to detect which implementation
should be used, and falls back onto an ordered list of known implementations.
common/logging/core/src/main/java/io/apiman/common/logging/ApimanLoggerFactory.java