sleep 
Sleep function using Promise.
Parameters
milliseconds::number
Returns
Promise:boolean
Examples
javascript
await sleep(1000); // 1s
sleep(5000).then(() => {
// continue
});dart
await sleep(1000); // 1s
sleep(5000).then(() => {
// continue
});python
sleep(1000) # 1s (blocks synchronously)
sleep(5000)
# continue