do not discover while printing

Inspectron.Epson/Queue/PrintServer.cs

@@ -6,18 +6,40 @@ public class PrintServer
     private readonly IPrintService _printService;
     private readonly ILogger _logger;
     private readonly ConcurrentDictionary<string, PrinterQueue> _printerQueues;
+    private readonly ReaderWriterLockSlim _printDiscoveryLock = new();
 
     public PrintServer(IPrintService printService, ILogger logger)
     {
         _printService = printService;
         _logger = logger;
         _printerQueues = new ConcurrentDictionary<string, PrinterQueue>();
-        
+
     }
 
+    /// <summary>
+    /// Acquires a read lock for print operations. Multiple print operations can run concurrently.
+    /// </summary>
+    public void EnterPrintLock() => _printDiscoveryLock.EnterReadLock();
+
+    /// <summary>
+    /// Releases the read lock after a print operation completes.
+    /// </summary>
+    public void ExitPrintLock() => _printDiscoveryLock.ExitReadLock();
+
+    /// <summary>
+    /// Acquires a write lock for discovery operations. This blocks until all print operations complete
+    /// and prevents new print operations from starting.
+    /// </summary>
+    public void EnterDiscoveryLock() => _printDiscoveryLock.EnterWriteLock();
+
+    /// <summary>
+    /// Releases the write lock after discovery completes.
+    /// </summary>
+    public void ExitDiscoveryLock() => _printDiscoveryLock.ExitWriteLock();
+
     public void RegisterPrinter(string printerIp)
     {
-        var queue = new PrinterQueue(printerIp, _printService, _logger);
+        var queue = new PrinterQueue(printerIp, _printService, _logger, this);
         if (_printerQueues.TryAdd(printerIp, queue))
         {
             queue.Start();