Function esp_http_client_set_event_handler 

pub unsafe extern "C" fn esp_http_client_set_event_handler(
    client: esp_http_client_handle_t,
    event_handler: http_event_handle_cb,
) -> esp_err_t

@brief Set the event handler for the client

@param[in] client The esp_http_client handle @param[in] event_handler The event handler

@return - ESP_OK - ESP_ERR_INVALID_ARG