Function Explanation: check_load_time

The check_load_time function does the following:

1. Writes the header for the report, including the current date and time, to the report file.
2. Iterates over each URL in the URLS array.
3. For each URL, it uses curl to measure the total time taken to load the page. The curl command is used with the following options:
   • -o /dev/null: Discards the output.
   • -s: Silent mode, which suppresses progress and error messages.
   • -w '%{time_total}\n': Writes the total time, in seconds, that the request took to complete.
4. Appends the loading time for each URL to the report file in a human-readable format.
5. Prints a message indicating that the report has been saved.