diff --git a/src/h2load.h b/src/h2load.h
index 7fb0067a..4dd323ad 100644
--- a/src/h2load.h
+++ b/src/h2load.h
@@ -441,8 +441,8 @@ struct Client {
   int quic_recv_crypto_data(ngtcp2_crypto_level crypto_level,
                             const uint8_t *data, size_t datalen);
   int quic_handshake_completed();
-  int quic_recv_stream_data(int64_t stream_id, int fin, const uint8_t *data,
-                            size_t datalen);
+  int quic_recv_stream_data(uint32_t flags, int64_t stream_id,
+                            const uint8_t *data, size_t datalen);
   int quic_acked_stream_data_offset(int64_t stream_id, size_t datalen);
   int quic_stream_close(int64_t stream_id, uint64_t app_error_code);
   int quic_stream_reset(int64_t stream_id, uint64_t app_error_code);
diff --git a/src/h2load_http3_session.cc b/src/h2load_http3_session.cc
index aac8df45..3fad5dc7 100644
--- a/src/h2load_http3_session.cc
+++ b/src/h2load_http3_session.cc
@@ -343,10 +343,10 @@ int Http3Session::init_conn() {
   return 0;
 }
 
-ssize_t Http3Session::read_stream(int64_t stream_id, const uint8_t *data,
-                                  size_t datalen, int fin) {
-  auto nconsumed =
-      nghttp3_conn_read_stream(conn_, stream_id, data, datalen, fin);
+ssize_t Http3Session::read_stream(uint32_t flags, int64_t stream_id,
+                                  const uint8_t *data, size_t datalen) {
+  auto nconsumed = nghttp3_conn_read_stream(
+      conn_, stream_id, data, datalen, flags & NGTCP2_STREAM_DATA_FLAG_FIN);
   if (nconsumed < 0) {
     std::cerr << "nghttp3_conn_read_stream: " << nghttp3_strerror(nconsumed)
               << std::endl;
diff --git a/src/h2load_http3_session.h b/src/h2load_http3_session.h
index 48b4f80c..cd3d96ba 100644
--- a/src/h2load_http3_session.h
+++ b/src/h2load_http3_session.h
@@ -58,8 +58,8 @@ public:
   int extend_max_local_streams();
   int64_t submit_request_internal();
 
-  ssize_t read_stream(int64_t stream_id, const uint8_t *data, size_t datalen,
-                      int fin);
+  ssize_t read_stream(uint32_t flags, int64_t stream_id, const uint8_t *data,
+                      size_t datalen);
   ssize_t write_stream(int64_t &stream_id, int &fin, nghttp3_vec *vec,
                        size_t veccnt);
   int block_stream(int64_t stream_id);
diff --git a/src/h2load_quic.cc b/src/h2load_quic.cc
index 6fb587dc..10b7caa4 100644
--- a/src/h2load_quic.cc
+++ b/src/h2load_quic.cc
@@ -71,11 +71,11 @@ int handshake_completed(ngtcp2_conn *conn, void *user_data) {
 int Client::quic_handshake_completed() { return connection_made(); }
 
 namespace {
-int recv_stream_data(ngtcp2_conn *conn, int64_t stream_id, int fin,
+int recv_stream_data(ngtcp2_conn *conn, uint32_t flags, int64_t stream_id,
                      uint64_t offset, const uint8_t *data, size_t datalen,
                      void *user_data, void *stream_user_data) {
   auto c = static_cast<Client *>(user_data);
-  if (c->quic_recv_stream_data(stream_id, fin, data, datalen) != 0) {
+  if (c->quic_recv_stream_data(flags, stream_id, data, datalen) != 0) {
     // TODO Better to do this gracefully rather than
     // NGTCP2_ERR_CALLBACK_FAILURE.  Perhaps, call
     // ngtcp2_conn_write_application_close() ?
@@ -85,14 +85,14 @@ int recv_stream_data(ngtcp2_conn *conn, int64_t stream_id, int fin,
 }
 } // namespace
 
-int Client::quic_recv_stream_data(int64_t stream_id, int fin,
+int Client::quic_recv_stream_data(uint32_t flags, int64_t stream_id,
                                   const uint8_t *data, size_t datalen) {
   if (worker->current_phase == Phase::MAIN_DURATION) {
     worker->stats.bytes_total += datalen;
   }
 
   auto s = static_cast<Http3Session *>(session.get());
-  auto nconsumed = s->read_stream(stream_id, data, datalen, fin);
+  auto nconsumed = s->read_stream(flags, stream_id, data, datalen);
   if (nconsumed == -1) {
     return -1;
   }
@@ -570,10 +570,15 @@ int Client::write_quic() {
     auto v = vec.data();
     auto vcnt = static_cast<size_t>(sveccnt);
 
+    uint32_t flags = NGTCP2_WRITE_STREAM_FLAG_MORE;
+    if (fin) {
+      flags |= NGTCP2_WRITE_STREAM_FLAG_FIN;
+    }
+
     auto nwrite = ngtcp2_conn_writev_stream(
-        quic.conn, &ps.path, buf.data(), quic.max_pktlen, &ndatalen,
-        NGTCP2_WRITE_STREAM_FLAG_MORE, stream_id, fin,
-        reinterpret_cast<const ngtcp2_vec *>(v), vcnt, timestamp(worker->loop));
+        quic.conn, &ps.path, buf.data(), quic.max_pktlen, &ndatalen, flags,
+        stream_id, reinterpret_cast<const ngtcp2_vec *>(v), vcnt,
+        timestamp(worker->loop));
     if (nwrite < 0) {
       switch (nwrite) {
       case NGTCP2_ERR_STREAM_DATA_BLOCKED: