diff --git a/apps/EchoClient.cpp b/apps/EchoClient.cpp
index 174f3cc80e4f53a30ab9ad833010b18dafddae1c..777225b45c94ea513e29162cd4b58c2a50795907 100644
--- a/apps/EchoClient.cpp
+++ b/apps/EchoClient.cpp
@@ -13,6 +13,7 @@
 #include <cerrno>		// for errno, ECANCELED
 #include <chrono>		// for nanoseconds, duration, durat...
 #include <cstdint>	// for uint64_t, int32_t
+#include <cstdio>
 #include <cstdlib>	// for size_t, strtol, exit, EXIT_F...
 #include <cstring>	// for memcmp
 #include <iomanip>
@@ -167,6 +168,8 @@ static void clientFunc(uint64_t client_id, Semaphore& readySem, Semaphore& start
 
 	size_t i = 0;
 	while (i < iterations && !terminate.load(std::memory_order_relaxed)) {
+		snprintf(outBuf, size, "%ld:%ld", client_id, i);
+
 		SendFuture sendFuture(client_sock, outBuf, size, MSG_NOSIGNAL);
 		RecvFuture recvFuture(client_sock, inBuf, size, MSG_WAITALL);