sd-netlink: introduce netlink_get_reply_callback_count()

src/libsystemd/sd-netlink/netlink-util.h

@@ -107,5 +107,7 @@ int rtattr_read_nexthop(const struct rtnexthop *rtnh, size_t size, int family, O
 
 void netlink_seal_message(sd_netlink *nl, sd_netlink_message *m);
 
+size_t netlink_get_reply_callback_count(sd_netlink *nl);
+
 /* TODO: to be exported later */
 int sd_netlink_sendv(sd_netlink *nl, sd_netlink_message **messages, size_t msgcnt, uint32_t **ret_serial);

src/libsystemd/sd-netlink/sd-netlink.c

@@ -458,6 +458,12 @@ static int timeout_compare(const void *a, const void *b) {
         return CMP(x->timeout, y->timeout);
 }
 
+size_t netlink_get_reply_callback_count(sd_netlink *nl) {
+        assert(nl);
+
+        return hashmap_size(nl->reply_callbacks);
+}
+
 int sd_netlink_call_async(
                 sd_netlink *nl,
                 sd_netlink_slot **ret_slot,