What are the alternatives to usleep() function for waiting in PHP scripts?

The usleep() function in PHP is used to pause the execution of a script for a specified number of microseconds. However, this function may not be available on all systems or may not be the most efficient way to wait in a script. One alternative to usleep() is to use the sleep() function, which pauses the script for a specified number of seconds. Another option is to use the time_sleep_until() function, which waits until a specified timestamp has been reached. Additionally, you can use a combination of time() and usleep() to achieve a more precise wait time.

// Using sleep() function
sleep(1); // Pause the script for 1 second

// Using time_sleep_until() function
$future_timestamp = time() + 5; // Set a future timestamp 5 seconds from now
time_sleep_until($future_timestamp);

// Using a combination of time() and usleep()
$start_time = microtime(true);
$wait_time = 0.5; // Wait for 0.5 seconds
while(microtime(true) - $start_time < $wait_time){
    usleep(10000); // Pause for 0.01 seconds
}