diff --git a/sf-buffer/src/sf_replay.cpp b/sf-buffer/src/sf_replay.cpp
index e4bc89f..4f05343 100644
--- a/sf-buffer/src/sf_replay.cpp
+++ b/sf-buffer/src/sf_replay.cpp
@@ -93,7 +93,8 @@ int main (int argc, char *argv[]) {
 
     auto ctx = zmq_ctx_new();
     auto socket = zmq_socket(ctx, ZMQ_PUSH);
-    int sndhwm = REPLAY_BLOCK_SIZE;
+    // The +1 is important so we pre-load the next chunk.
+    int sndhwm = REPLAY_BLOCK_SIZE + 1;
     if (zmq_setsockopt(socket, ZMQ_SNDHWM, &sndhwm, sizeof(sndhwm)) != 0) {
         throw runtime_error(strerror (errno));
     };