bpf_testmod_union_arg_1
int BPF_PROG2(test_union_arg_1, union bpf_testmod_union_arg_1, a, int, b, int, c)
bpf_testmod_test_union_arg_1(union bpf_testmod_union_arg_1 a, int b, int c)
union bpf_testmod_union_arg_1 union_arg1 = { .arg = {1} };