Update README.md

Author: stephen-soltesz

README.md

@@ -95,6 +95,11 @@ Download server #1 - rate 8.24 Mbps, rtt 12.17ms, elapsed 0.0128s, application r
 Download client #1 - Avg 30.51 Mbps, MinRTT 10.99ms, elapsed 0.0433s, application r/w: 0/164972
 ```
 
+Every TCP connection has performance metrics accessible from the server end and
+the client end. The `minimal-download` client reports metrics generated by the
+server side and concludes with client side average performance. Client side
+performance is comparable to what a user (or user application) would see.
+
 ## Measurements
 
 The application, network, and kernel metrics may differ to the degree