#include <nng/nng.h>
#include <nng/supplemental/tls/tls.h>
void nng_tls_config_alloc(nng_tls_config *cfg);The nng_tls_config_hold() increments the reference count on
the configuration object named by cfg, thereby preventing it
from being freed while in use.
The hold can be released by calling
nng_tls_config_free().
Multiple holds can be placed on a configuration object; the object will not be freed until the last hold is released.