Implemented hearthbit client side + tests

Source/Components/Interfaces/UDPStream/UDPSClient.h

@@ -92,6 +92,11 @@ public:
     /** Default delay between reconnect attempts (seconds). */
     static const uint32 UDPS_CLIENT_DEFAULT_RECONNECT_DELAY_S = 2u;
 
+    /** Default unicast keepalive interval (seconds). UDPSServer evicts silent
+     *  unicast clients after its ClientTimeout (default 30 s); the client
+     *  re-sends an ACK on this interval to stay registered. 0 disables. */
+    static const uint32 UDPS_CLIENT_DEFAULT_KEEPALIVE_INTERVAL_S = 15u;
+
     /** Default maximum payload size (bytes, excluding 17-byte header). */
     static const uint32 UDPS_CLIENT_DEFAULT_MAX_PAYLOAD = 1400u;
 
@@ -115,6 +120,7 @@ public:
      *  - DataPort        (uint16) UDP multicast data port (defaults to Port+1).
      *  - SilenceTimeout  (uint32) Seconds of no data before reconnect. Default 5.
      *  - ReconnectDelay  (uint32) Seconds to wait between reconnect attempts. Default 2.
+     *  - KeepAliveInterval (uint32) Seconds between unicast keepalive ACKs. Default 15. 0 disables.
      *  - MaxPayloadSize  (uint32) Max payload bytes per datagram, excluding header. Default 1400.
      *  - CPUMask         (uint32) CPU affinity mask for the receive thread. Default 0xFFFFFFFF.
      *  - StackSize       (uint32) Stack size for the receive thread. Default 65536.
@@ -168,6 +174,8 @@ private:
     // -------------------------------------------------------------------------
     bool Connect();
     void Disconnect();
+    /** Send a keepalive ACK to the server (unicast only, same socket). */
+    void SendKeepAlive();
     bool ReceiveAndProcess();
 
     bool ConnectUnicast();
@@ -196,6 +204,7 @@ private:
     bool         useMulticast;
     uint64       silenceTimeoutTicks;
     uint64       reconnectDelayTicks;
+    uint64       keepAliveIntervalTicks; ///< 0 = keepalive disabled
     uint32       maxPayloadSize;
     uint32       cpuMask;
     uint32       stackSize;
@@ -209,6 +218,7 @@ private:
     bool                connected;
     uint64              lastDataTicks;  ///< Ticks at last received DATA/CONFIG
     uint64              disconnectTick; ///< Ticks when we disconnected (for delay)
+    uint64              lastKeepAliveTicks; ///< Ticks at last keepalive ACK sent
 
     // Unicast
     BasicUDPSocket recvSocket;  ///< Bound to ephemeral port; receives DATA