Co-authored-by: Joe Chen <jc@unknwon.io>
* 修正12.3章中的提示 * 根据liuhm98的意见,重新对12.3章末尾的提示做了修正
Fixed a that if dstName file's length longer than srcName file io.Copy will cover only part content of srcName file. If file srcName 's content is "abc", dstName's content is "1234" ,the result of io.Copy(dst, src) is "abc4" not "abc"