SSL_get_ex_new_index
ex_context_id = SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL);
ex_handle_id = SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL);
ex_data_idx = SSL_get_ex_new_index(0, "ex data", NULL, NULL, NULL);
stats_idx = SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL);