Common tree insert function for QUIC and UDP connections. Previously, ngx_udp_rbtree_insert_value() was used for plain UDP and ngx_quic_rbtree_insert_value() was used for QUIC. Because of this it was impossible to initialize connection tree in ngx_create_listening() since this function is not aware what kind of listening it creates. Now ngx_udp_rbtree_insert_value() is used for both QUIC and UDP. To make is possible, a generic key field is added to ngx_udp_connection_t. It keeps client address for UDP and connection ID for QUIC.

--- a/src/stream/ngx_stream.c
+++ b/src/stream/ngx_stream.c
@@ -518,11 +518,6 @@ ngx_stream_optimize_servers(ngx_conf_t *
             ls->reuseport = addr[i].opt.reuseport;
 #endif
 
-#if !(NGX_WIN32)
-            ngx_rbtree_init(&ls->rbtree, &ls->sentinel,
-                            ngx_udp_rbtree_insert_value);
-#endif
-
             stport = ngx_palloc(cf->pool, sizeof(ngx_stream_port_t));
             if (stport == NULL) {
                 return NGX_CONF_ERROR;