public static void clear(RequestContext ctx) {
        requireNonNull(ctx, "ctx");

        synchronized (ctx) {
            final Object2ObjectMap<String, String> oldMap = getMap(ctx);
            if (!oldMap.isEmpty()) {
                ctx.setAttr(MAP, Object2ObjectMaps.emptyMap());
            }
        }
    }
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