in servo_pkg/src/servo_mgr.cpp [155:162]
void ServoMgr::setGPIOHdl(const std::shared_ptr<rmw_request_id_t> request_header,
const std::shared_ptr<deepracer_interfaces_pkg::srv::ServoGPIOSrv::Request> req,
std::shared_ptr<deepracer_interfaces_pkg::srv::ServoGPIOSrv::Response> res) {
(void)request_header;
bool ret = calibrateServo(GPIO_CHANNEL, req->enable);
res->error = ret ? 0 : 1;
}