Golang and Arduino

void setup() {
    Serial.begin(9600);

    // get data from Serial.readStringUntil('\n'); to memory
    String data="FFFFFFFF 00FFFFFF 0000FFFF 000000FF";
    // store length of data
    int iend = data.length() - 1; 
    // current begin index
    int index=0;
    // next index
    int next_index;
    do{
        next_index=data.indexOf(' ',index);

        String hexcode=data.substring(index, next_index);

        index=next_index+1;

        unsigned long bigNumber = (unsigned long)strtoul(hexcode.c_str(), 0, 16);

        // add number to array

        Serial.println(bigNumber);

     }while((next_index!=-1)&&(next_index<iend));
}

void loop() {

}

You can send command without any libraries to arduino. in this example "message" ( protocol) is "2 chars + number + number" -> "GO 123 -512" 

void setup() {
  Serial.begin(9600);
}

void loop() {
  // check if something on Serial
  if(Serial.available()) {
    // define variables
    long number1, number2;
    char cmd[2];
    memset(cmd, 0, 2);
    // read data from Serial
    String s = Serial.readStringUntil('\n');
    char buff[64];
    memset(buff, 0, 64);
    // convert string to char array
    s.toCharArray(buff, 64);
    // parse cmd to variables
    sscanf(buff, "%2c %ld %ld",cmd, &number1, &number2);
    char pr[128];
    memset(pr, 0, 128);
    // print template to buffer
    sprintf(pr, "got 2 numbers from serial: %ld and %ld and command %s", number1, number2, cmd);
    // print buffer back to Serial
    Serial.println(pr);
  }

}