}
    }

    /**
     * Performs witness unregistration.
     *
     * @param request the unregistration request
     * @return the unregistration response
     * @throws IOException if the RPC call fails
     */
    public WitnessUnregisterResponse unregister(WitnessUnregisterRequest request) throws IOException {
        if (!connected) {

        // 4. Cleanup and unregistration
        assertTrue(mockService.unregisterWitness(regId));
        assertEquals(0, mockService.getRegistrationCount());
        assertFalse(mockService.hasRegistration(regId));

        // 5. Verify heartbeat fails after unregistration
        assertFalse(mockService.processHeartbeat(regId, 4));
    }

    /**

        /**
         * Called when a witness registration fails.
         *
         * @param registration the failed registration
         * @param error the error that occurred
         */
        void onRegistrationFailed(WitnessRegistration registration, Exception error);

        /**
         * Called when a witness registration expires.
         *
         * @param registration the expired registration
         */

        WitnessRegistration registration = future.get(5, TimeUnit.SECONDS);

        assertNotNull(registration);
        assertEquals(WitnessRegistrationState.REGISTERED, registration.getState());
        assertEquals("\\\\server\\share", registration.getShareName());
        assertEquals(serverAddress, registration.getServerAddress());

        log.error("Witness registration failed: {}", registration.getRegistrationId(), error);
    }
    
    @Override
    public void onRegistrationExpired(WitnessRegistration registration) {
        log.warn("Witness registration expired: {}", registration.getRegistrationId());
        // Could attempt re-registration here
    }
}

├── WitnessRegistration.java     - Client registration with witness
├── WitnessNotification.java     - Notification handling
├── ResourceChange.java          - Resource change events
└── WitnessTransport.java       - Witness-specific RPC transport
```

#### 6.2 Implementation Tasks
- [ ] Implement Witness RPC protocol
- [ ] Create witness service discovery
- [ ] Implement client registration
- [ ] Add notification callback mechanism

    RDMA_WRITE,          // Remote direct write operations  
    RDMA_SEND_RECEIVE,   // Traditional send/receive with RDMA
    MEMORY_REGISTRATION, // Dynamic memory registration
    FAST_REGISTRATION   // Fast memory region registration
}

public class RdmaCapabilities {
    // RDMA transform capabilities
    public static final int SMB_DIRECT_RESPONSE_REQUESTED = 0x00000001;
    
    // Default RDMA settings

        FunCustodial.checkSpecifiedProperty(this, propertyName, __specifiedProperties);
    }

    protected void registerSpecifiedProperty(String propertyName) { // basically called by modified property registration
        if (__specifiedProperties != null) { // normally false, true if e.g. setting after selected
            __specifiedProperties.addPropertyName(propertyName);
        }
    }

        this.notifications = new ArrayList<>();
    }

    /**
     * Creates a new WitnessAsyncNotify RPC message with the specified context handle.
     *
     * @param contextHandle the context handle from registration
     */
    public WitnessAsyncNotifyMessage(byte[] contextHandle) {
        super(WITNESS_ASYNC_NOTIFY);
        this.contextHandle = contextHandle != null ? contextHandle.clone() : new byte[20];

        FunCustodial.checkSpecifiedProperty(this, propertyName, __specifiedProperties);
    }

    protected void registerSpecifiedProperty(String propertyName) { // basically called by modified property registration
        if (__specifiedProperties != null) { // normally false, true if e.g. setting after selected
            __specifiedProperties.addPropertyName(propertyName);
        }
    }