The difference between parameters : connection timeout and dial timeout

[mingkwind]

I test them in my PC.
I find that the parameter (dial timeout) is the controller of connection timeout but the parameter (connection timeout) can not control connection timeout.
Is there something wrong in the Introduction for the parameter connection timeout?

[mingkwind]

dataSourceName := fmt.Sprintf("sqlserver://%v:%v@%v:%v?database=%v&dial+timeout=%v",
service.Username, service.Password, service.Ip, service.Port, "master", timeout)
db, err := sql.Open("mssql", dataSourceName)