Add some additional delay when sending pings without there being activity on receive side

src/core/ext/transport/chttp2/transport/writing.cc

@@ -81,7 +81,9 @@ static void maybe_initiate_ping(grpc_chttp2_transport* t) {
       (t->keepalive_permit_without_calls == 0 &&
        grpc_chttp2_stream_map_size(&t->stream_map) == 0)
           ? 7200 * GPR_MS_PER_SEC
-          : t->ping_policy.min_sent_ping_interval_without_data;
+          : (t->ping_policy.min_sent_ping_interval_without_data +
+             GPR_MS_PER_SEC); /* A second is added to deal with network delays
+                                 and timing imprecision */
   grpc_millis next_allowed_ping =
       t->ping_state.last_ping_sent_time + next_allowed_ping_interval;