remote var callback docs

ESPMegaPRO-OS-SDK/lib/ESPMegaPRO/RemoteVariable.cpp

@@ -135,10 +135,22 @@ void RemoteVariable::setValue(const char* value) {
     this->iot->publish(this->setValueTopic, value);
 }
 
+/**
+ * @brief Register a callback for value change
+ * This method will be called when the value of the variable changes on the remote device
+ * @param callback The callback function
+ * @return uint8_t The handler for the callback
+*/
 uint8_t RemoteVariable::registerCallback(std::function<void(char*)> callback) {
     this->valueChangeCallback[this->valueChangeCallbackCount] = callback;
     return valueChangeCallbackCount++;
 }
+
+/**
+ * @brief Unregister a callback
+ * This method is used to unregister a callback
+ * @param handler The handler of the callback
+*/
 void RemoteVariable::unregisterCallback(uint8_t handler) {
     this->valueChangeCallback.erase(handler);
 }