public static void pop(RequestContext current, @Nullable RequestContext toRestore) {
        requireNonNull(current, "current");
        requestContextStorage.pop(current, toRestore);
    }
Pops the current {@link RequestContext} in the storage and pushes back the specified {@code toRestore}.
core/src/main/java/com/linecorp/armeria/internal/common/RequestContextUtil.java