nng_log_set_level3

#include <nng/nng.h>
typedef enum nng_log_level {
        NNG_LOG_NONE   = 0, // used for filters only, NNG suppresses these
        NNG_LOG_ERR    = 3,
        NNG_LOG_WARN   = 4,
        NNG_LOG_NOTICE = 5,
        NNG_LOG_INFO   = 6,
        NNG_LOG_DEBUG  = 7
} nng_log_level;
void nng_log_set_level(nng_log_level level);