nng_stat_find_socket always returns the same stats node

[cadaker]

Describe the bug
I'm running nng_stat_find_socket on two different sockets, but the same stat node is returned for both.

Expected behavior
Different sockets should have different stats, and nng_stat_find_socket should find the stats for the socket given.

Actual Behavior
It seems like the find call just retrieves the first socket it finds, regardless of the socket passed in.

To Reproduce
This test case fails for me:

    nng_socket s0{};
    nng_socket s1{};
    nng_pub0_open(&s0);
    nng_pub0_open(&s1);

    nng_stat* stats = nullptr;
    nng_stats_get(&stats);
    nng_stat* s0stat = nng_stat_find_socket(stats, s0);
    nng_stat* s1stat = nng_stat_find_socket(stats, s1);
    CHECK(s0stat != s1stat);

Environment Details

• NNG version: master
• Operating system and version: Ubuntu 20.04
• Compiler and language used: g++ 9.4.0
• Shared or static library: static

Additional context
When looking at the stats dump, all sockets are listed with the header of Socket#0. The "id" node below shows the correct socket id, though. That is maybe relevant information?

[gdamore]

Ooops.