Wait for sub requests to finish before deleting the node

Fixes https://gitlab.com/uplex/varnish/libvdp-pesi/-/issues/10

src/node.c

@@ -44,6 +44,7 @@
 #include "node_assert.h"
 #include "node_mempool.h"
 #include "pesi.h"
+#include "pesi_tree.h"
 
 #include "misc.h"
 
@@ -623,6 +624,13 @@ fini_subreq(const struct vdp_ctx *vdx, struct node *node)
 
 	assert(node->type == T_SUBREQ);
 
+	if (node->subreq.done == 0) {
+		CAST_OBJ_NOTNULL(subreq, node->subreq.req, REQ_MAGIC);
+		CAST_OBJ_NOTNULL(pesi, subreq->transport_priv, PESI_MAGIC);
+		CHECK_OBJ_NOTNULL(pesi->pesi_tree, PESI_TREE_MAGIC);
+		CHECK_OBJ_NOTNULL(pesi->pesi_tree->tree, BYTES_TREE_MAGIC);
+		subreq_wait_done(node, pesi->pesi_tree->tree);
+	}
 	AN(node->subreq.done);
 
 	if (node->subreq.req == NULL) {