src/main/java/com/arpnetworking/logback/KeyValueEncoder.java
Map<String, Object> createSafeContext(final ILoggingEvent event) {
        return createSafeContext(event, Collections.emptyList(), Collections.emptyList());
    }
Map<String, Object> createSafeContext(final ILoggingEvent event) {
        return createSafeContext(event, Collections.emptyList(), Collections.emptyList());
    }
/* package private