private static Map<String, String> maybeCloneThreadLocalMap(Map<String, String> threadLocalMap) {
            // Copy only when we retrieved the thread local map from `getPropertyMap()`.
            return delegateGetPropertyMap != null ? new Object2ObjectOpenHashMap<>(threadLocalMap)
                                                  : threadLocalMap;
        }
Unbinds all request-scoped {@link MDC} properties from the specified {@link RequestContext}.

@param ctx the {@link RequestContext}
core/src/main/java/com/linecorp/armeria/common/logging/RequestScopedMdc.java