Arduino Arduino Library for ESP8266, ESP32, Portenta_H7, STM32 and RP2040W asynchronous MQTT client implementation. This library, ported to support ESP32, WT32_ETH01 (ESP32 + LAN8720), ESP8266, Portenta_H7 (Ethernet or WiFi) and STM32 (LAN8742A or LAN8720 Ethernet), Teensy 4.1 using QNEthernet, RASPBERRY_PI_PICO_W with CYW43439 WiFi. Currently supporting TLS/SSL for ESP32 only
Sorry, found no other way.
Where are the parameters explained in your documentation? e.g. mqttClient.publish(PubTopic, 0, true, "ESP32 Test");