use this_thread::sleep_for instead of sleep
use this_thread::sleep_for instead of sleep

LianaHus/solidity,arkpar/solidity,ruchevits/solidity,ruchevits/solidity,chriseth/solidity-doc-test,chriseth/solidity,douglas-larocca/solidity,debris/solidity,ruchevits/solidity,ethers/solidity,vaporry/solidity,ruchevits/solidity,gluk256/solidity,shahankhatch/solidity