diff --git a/quinn-proto/src/connection/mod.rs b/quinn-proto/src/connection/mod.rs
index a8ec1dcc0c..94264f044c 100644
--- a/quinn-proto/src/connection/mod.rs
+++ b/quinn-proto/src/connection/mod.rs
@@ -639,6 +639,7 @@ impl Connection {
                         congestion_blocked = true;
                         // We continue instead of breaking here in order to avoid
                         // blocking loss probes queued for higher spaces.
+                        trace!("blocked by congestion control");
                         continue;
                     }
 
@@ -655,6 +656,7 @@ impl Connection {
                         congestion_blocked = true;
                         // Loss probes should be subject to pacing, even though
                         // they are not congestion controlled.
+                        trace!("blocked by pacing");
                         break;
                     }
                 }
@@ -3161,6 +3163,7 @@ impl Connection {
         while buf.len() + Datagram::SIZE_BOUND < max_size && space_id == SpaceId::Data {
             match self.datagrams.write(buf, max_size, max_datagram_size) {
                 true => {
+                    trace!("DATAGRAM");
                     sent_datagrams = true;
                     sent.non_retransmits = true;
                     self.stats.frame_tx.datagram += 1;