MINOR: quic: Add a function to list remaining RX packets by encryption level

This is only to debug some issues which cause the RX buffer saturation
with "Too big packet" traces.
diff --git a/include/haproxy/xprt_quic.h b/include/haproxy/xprt_quic.h
index fda8580..b731da2 100644
--- a/include/haproxy/xprt_quic.h
+++ b/include/haproxy/xprt_quic.h
@@ -1138,6 +1138,32 @@
 	HA_RWLOCK_WRUNLOCK(QUIC_LOCK, &qel->rx.pkts_rwlock);
 }
 
+static inline void qc_list_qel_rx_pkts(struct quic_enc_level *qel)
+{
+	struct eb64_node *node;
+
+	HA_RWLOCK_RDLOCK(QUIC_LOCK, &qel->rx.pkts_rwlock);
+	node = eb64_first(&qel->rx.pkts);
+	while (node) {
+		struct quic_rx_packet *pkt;
+
+		pkt = eb64_entry(&node->node, struct quic_rx_packet, pn_node);
+		fprintf(stderr, "pkt@%p type=%d pn=%llu\n",
+		        pkt, pkt->type, (ull)pkt->pn_node.key);
+		node = eb64_next(node);
+	}
+	HA_RWLOCK_RDUNLOCK(QUIC_LOCK, &qel->rx.pkts_rwlock);
+}
+
+static inline void qc_list_all_rx_pkts(struct quic_conn *qc)
+{
+	fprintf(stderr, "REMAINING QEL RX PKTS:\n");
+	qc_list_qel_rx_pkts(&qc->els[QUIC_TLS_ENC_LEVEL_INITIAL]);
+	qc_list_qel_rx_pkts(&qc->els[QUIC_TLS_ENC_LEVEL_EARLY_DATA]);
+	qc_list_qel_rx_pkts(&qc->els[QUIC_TLS_ENC_LEVEL_HANDSHAKE]);
+	qc_list_qel_rx_pkts(&qc->els[QUIC_TLS_ENC_LEVEL_APP]);
+}
+
 void quic_set_tls_alert(struct quic_conn *qc, int alert);
 int quic_set_app_ops(struct quic_conn *qc, const unsigned char *alpn, size_t alpn_len);
 ssize_t quic_lstnr_dgram_read(struct buffer *buf, size_t len, void *owner,
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 9c6ca9c..9d5f6eb 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -4173,6 +4173,7 @@
 		if (b_contig_space(&qc->rx.buf) < pkt->len) {
 			HA_RWLOCK_WRUNLOCK(QUIC_LOCK, &qc->rx.buf_rwlock);
 			TRACE_PROTO("Too big packet", QUIC_EV_CONN_LPKT, qc->conn, pkt, &pkt->len);
+			qc_list_all_rx_pkts(qc);
 			goto err;
 		}
 	}