Auto: twincat-3.1 — per-tag MaxDelay tuning

Closes #313

tests/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.IntegrationTests/TwinCatProject/README.md

@@ -71,6 +71,12 @@ GVL_Fixture.nCounter := GVL_Fixture.nCounter + 1;
 - `PlcTask` — cyclic, 10 ms interval, priority 20
 - Assigned to `MAIN`
 
+> **Note (PR 3.1 / #313)**: `GVL_Fixture.nCounter` doubles as the
+> coalescing-test driver for `TwinCATMaxDelayTests`. The 10 ms cycle +
+> per-cycle increment in `MAIN` means a no-coalescing subscriber sees ~100
+> events / s; with `MaxDelayMs=500` the test asserts ≤ 3 events / s. No new
+> project state required.
+
 ## Performance scenarios
 
 PR 2.1 (ADS Sum-read / Sum-write) ships an opt-in perf-tier integration test