Device: Add isOnlineSupported()

include/icsneo/device/device.h

@@ -685,6 +685,8 @@ public:
 		uint64_t pos, uint8_t* into, uint64_t amount, std::optional<VSAMetadata> metadata = std::nullopt
 	);
 
+	virtual bool isOnlineSupported() const { return true; }
+
 protected:
 	bool online = false;
 	int messagePollingCallbackID = 0;

include/icsneo/device/tree/radmoon2/radmoon2base.h

@@ -64,6 +64,8 @@ public:
 
 	virtual uint8_t getPhyAddrOrPort() const = 0;
 
+	bool isOnlineSupported() const override { return false; }
+
 protected:
 	using Device::Device;
 

include/icsneo/device/tree/radmoon3/radmoon3.h

@@ -25,6 +25,8 @@ public:
 
 	bool getEthPhyRegControlSupported() const override { return true; }
 
+	bool isOnlineSupported() const override { return false; }
+
 protected:
 	RADMoon3(neodevice_t neodevice, const driver_factory_t& makeDriver) : Device(neodevice) {
 		initialize<RADMoon3Settings>(makeDriver);

include/icsneo/device/tree/vividcan/vividcan.h

@@ -27,6 +27,8 @@ public:
 		return false;
 	}
 
+	bool isOnlineSupported() const override { return false; }
+
 protected:
 	VividCAN(neodevice_t neodevice, const driver_factory_t& makeDriver) : Device(neodevice) {
 		initialize<VividCANSettings>(makeDriver);