@Override
        @Nullable
        public String get(String key) {
            final RequestContext ctx = RequestContext.currentOrNull();
            if (ctx != null) {
                final String value = RequestScopedMdc.get(ctx, key);
                if (value != null) {
                    return value;
                }
            }

            return delegate.get(key);
        }
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