Auto: twincat-3.1 — per-tag MaxDelay tuning

Closes #313

src/ZB.MOM.WW.OtOpcUa.Driver.TwinCAT.Cli/Commands/SubscribeCommand.cs

@@ -20,9 +20,18 @@ public sealed class SubscribeCommand : TwinCATCommandBase
         "String / WString / Time / Date / DateTime / TimeOfDay (default DInt).")]
     public TwinCATDataType DataType { get; init; } = TwinCATDataType.DInt;
 
-    [CommandOption("interval-ms", 'i', Description = "Publishing interval ms (default 1000).")]
+    [CommandOption("interval-ms", 'i', Description =
+        "Cycle time ms — minimum interval between change checks the PLC runtime applies " +
+        "(default 1000). Different from --max-delay-ms; see help for that flag.")]
     public int IntervalMs { get; init; } = 1000;
 
+    [CommandOption("max-delay-ms", Description =
+        "Per-tag MaxDelay in ms (PR 3.1, issue #313) — upper bound on how long the runtime " +
+        "can buffer / coalesce change events before dispatch. 0 (default) = fire ASAP, no " +
+        "coalescing. Larger values (e.g. 500) reduce event rate on bursty signals so the " +
+        "OPC UA queue downstream doesn't flood. Distinct from --interval-ms (the cycle).")]
+    public int MaxDelayMs { get; init; } = 0;
+
     public override async ValueTask ExecuteAsync(IConsole console)
     {
         ConfigureLogging();
@@ -34,7 +43,8 @@ public sealed class SubscribeCommand : TwinCATCommandBase
             DeviceHostAddress: Gateway,
             SymbolPath: SymbolPath,
             DataType: DataType,
-            Writable: false);
+            Writable: false,
+            MaxDelayMs: MaxDelayMs > 0 ? MaxDelayMs : null);
         var options = BuildOptions([tag]);
 
         await using var driver = new TwinCATDriver(options, DriverInstanceId);
@@ -54,8 +64,9 @@ public sealed class SubscribeCommand : TwinCATCommandBase
             handle = await driver.SubscribeAsync([tagName], TimeSpan.FromMilliseconds(IntervalMs), ct);
 
             var mode = PollOnly ? "polling" : "ADS notification";
+            var coalesce = MaxDelayMs > 0 ? $", max-delay {MaxDelayMs}ms" : "";
             await console.Output.WriteLineAsync(
-                $"Subscribed to {SymbolPath} @ {IntervalMs}ms ({mode}). Ctrl+C to stop.");
+                $"Subscribed to {SymbolPath} @ {IntervalMs}ms ({mode}{coalesce}). Ctrl+C to stop.");
             try
             {
                 await Task.Delay(System.Threading.Timeout.InfiniteTimeSpan, ct);