text: #include <string.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include "handler.h"
  
  char* handler(char* payload) {
      fprintf(stderr, "This is a log\n");
      char* hello = "Hello from c smart contract: ";
      char* returnValue = calloc(strlen(payload) + strlen(hello) + 3, sizeof(char));
      strcat(returnValue, hello);
      strcat(returnValue, payload);
      return returnValue;
  }
  