private static void reportIgnoredStaticLoggerBinders(Set<URL> staticLoggerBinderPathSet) {
        if (staticLoggerBinderPathSet.isEmpty()) {
            return;
        }
        Reporter.warn("Class path contains SLF4J bindings targeting slf4j-api versions 1.7.x or earlier.");

        for (URL path : staticLoggerBinderPathSet) {
            Reporter.warn("Ignoring binding found at [" + path + "]");
        }
        Reporter.warn("See " + IGNORED_BINDINGS_URL + " for an explanation.");

    }
The value of PROVIDER.getMDCAdapter() can be null while PROVIDER has not yet initialized.

However, SLF4JServiceProvider implementations are expected to initialize their internal
MDCAdapter field in their constructor or on field declaration.
slf4j-api/src/main/java/org/slf4j/LoggerFactory.java