btf_named_start_id
u32 btf_named_start_id(const struct btf *btf, bool own);
btf_named_start_id(btf, false) - 1);
l = btf_named_start_id(btf, true);
int id = btf_named_start_id(btf, false) - 1;
cands = bpf_core_add_cands(cands, main_btf, btf_named_start_id(main_btf, true));
cands = bpf_core_add_cands(cands, mod_btf, btf_named_start_id(mod_btf, true));
for (i = btf_named_start_id(btf, true); i < n; i++) {