  */
 void request(void (*func)()) {
   int code;
+  // For Arduino UNO, it only supports 4-byte integer.
+  unsigned int failcounts = 0;
+  unsigned int delaytime;
+  // The outer loop is to keep sending requests to the slave until receiving a positive response
   do {
     JsonObject* response;
+    // The inner loop is to receive the response from the slave end after sending the request
     do {
       // TODO: Currently we hard-code the argument in the code. Would handle the problem that how to solve
       // multiple arguments.

    //Serial.println(info);
    switch (code){
      case FAIL:
        delay(1000);
        break;
      case MEASUREUNREG:
        exit(-1);
      case OK:
        break;
      default:
        exit(-1);


  Serial.flush();
}

