diff --git a/quic/core/qpack/fuzzer/qpack_round_trip_fuzzer.cc b/quic/core/qpack/fuzzer/qpack_round_trip_fuzzer.cc
index d2b8904..84c6948 100644
--- a/quic/core/qpack/fuzzer/qpack_round_trip_fuzzer.cc
+++ b/quic/core/qpack/fuzzer/qpack_round_trip_fuzzer.cc
@@ -19,6 +19,7 @@
 #include "net/third_party/quiche/src/quic/platform/api/quic_containers.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_fuzzed_data_provider.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_ptr_util.h"
+#include "net/third_party/quiche/src/quic/test_tools/qpack_encoder_peer.h"
 #include "net/third_party/quiche/src/spdy/core/spdy_header_block.h"
 
 namespace quic {
@@ -34,6 +35,12 @@
     encoder_.SetMaximumBlockedStreams(maximum_blocked_streams);
   }
 
+  ~EncodingEndpoint() {
+    // Every reference should be acknowledged.
+    CHECK_EQ(std::numeric_limits<uint64_t>::max(),
+             QpackEncoderPeer::smallest_blocking_index(&encoder_));
+  }
+
   void set_qpack_stream_sender_delegate(QpackStreamSenderDelegate* delegate) {
     encoder_.set_qpack_stream_sender_delegate(delegate);
   }
diff --git a/quic/test_tools/qpack_encoder_peer.cc b/quic/test_tools/qpack_encoder_peer.cc
index 4e4bb52..9719bdb 100644
--- a/quic/test_tools/qpack_encoder_peer.cc
+++ b/quic/test_tools/qpack_encoder_peer.cc
@@ -20,5 +20,11 @@
   return encoder->maximum_blocked_streams_;
 }
 
+// static
+uint64_t QpackEncoderPeer::smallest_blocking_index(
+    const QpackEncoder* encoder) {
+  return encoder->blocking_manager_.smallest_blocking_index();
+}
+
 }  // namespace test
 }  // namespace quic
diff --git a/quic/test_tools/qpack_encoder_peer.h b/quic/test_tools/qpack_encoder_peer.h
index b8a8cc7..2edf427 100644
--- a/quic/test_tools/qpack_encoder_peer.h
+++ b/quic/test_tools/qpack_encoder_peer.h
@@ -20,6 +20,7 @@
 
   static QpackHeaderTable* header_table(QpackEncoder* encoder);
   static uint64_t maximum_blocked_streams(const QpackEncoder* encoder);
+  static uint64_t smallest_blocking_index(const QpackEncoder* encoder);
 };
 
 }  // namespace test