private Iterable<LoggingProvider> loadServiceProviders() {
    CollectingServiceLoader<LoggingProvider> serviceLoader = new ListCollectingServiceLoader<>();
    Collection<LoggingProvider> loggingProviders =
        serviceLoader.loadServices(LoggingProvider.class);
    return loggingProviders;
  }
System property that may be used to override which {@code LoggingProvider} to use.
geode-core/src/main/java/org/apache/geode/logging/internal/LoggingProviderLoader.java