diff --git a/quic/state/StreamData.h b/quic/state/StreamData.h
index 245c2412a..04c5ffb78 100644
--- a/quic/state/StreamData.h
+++ b/quic/state/StreamData.h
@@ -345,6 +345,15 @@ struct QuicStreamLike {
       pendingWrites.splitAtMost(pendingWrites.chainLength());
     }
   }
+
+  [[nodiscard]] bool allBytesAckedTill(uint64_t offset) const {
+    if (ackedIntervals.empty()) {
+      return false;
+    }
+
+    return ackedIntervals.front().start == 0 &&
+        ackedIntervals.front().end >= offset;
+  }
 };
 
 struct QuicConnectionStateBase;
diff --git a/quic/state/test/StreamDataTest.cpp b/quic/state/test/StreamDataTest.cpp
index df1f18f12..00bb993d3 100644
--- a/quic/state/test/StreamDataTest.cpp
+++ b/quic/state/test/StreamDataTest.cpp
@@ -585,4 +585,49 @@ TEST(StreamDataTest, WriteBufferMetaRemovalNoChange) {
   EXPECT_EQ(state.writeBufMeta.length, 12);
 }
 
+TEST(StreamDataTest, AllBytesAckedTillEmptyAck) {
+  QuicConnectionStateBase qcsb(QuicNodeType::Client);
+  QuicStreamState state(0, qcsb);
+
+  EXPECT_TRUE(state.ackedIntervals.empty());
+  EXPECT_EQ(state.allBytesAckedTill(0), false);
+}
+
+TEST(StreamDataTest, AllBytesAckedTillNotStartAtZero) {
+  QuicConnectionStateBase qcsb(QuicNodeType::Client);
+  QuicStreamState state(0, qcsb);
+
+  EXPECT_TRUE(state.ackedIntervals.empty());
+  state.updateAckedIntervals(1, 5, false);
+  EXPECT_EQ(state.allBytesAckedTill(5), false);
+}
+
+TEST(StreamDataTest, AllBytesAckedTillNotEnoughLength) {
+  QuicConnectionStateBase qcsb(QuicNodeType::Client);
+  QuicStreamState state(0, qcsb);
+
+  EXPECT_TRUE(state.ackedIntervals.empty());
+  state.updateAckedIntervals(0, 5, false);
+  EXPECT_EQ(state.allBytesAckedTill(5), false);
+}
+
+TEST(StreamDataTest, AllBytesAckedPass) {
+  QuicConnectionStateBase qcsb(QuicNodeType::Client);
+  QuicStreamState state(0, qcsb);
+
+  EXPECT_TRUE(state.ackedIntervals.empty());
+  state.updateAckedIntervals(0, 6, false);
+  EXPECT_EQ(state.allBytesAckedTill(5), true);
+}
+
+TEST(StreamDataTest, AllBytesAckedDisjointIntervals) {
+  QuicConnectionStateBase qcsb(QuicNodeType::Client);
+  QuicStreamState state(0, qcsb);
+
+  EXPECT_TRUE(state.ackedIntervals.empty());
+  state.updateAckedIntervals(0, 2, false);
+  state.updateAckedIntervals(3, 5, false);
+  EXPECT_EQ(state.allBytesAckedTill(5), false);
+}
+
 } // namespace quic::test