Background
The Go driver by default uses the net.Dialer configured in connection_options.go. The behavior of net.Dialer’s DNS resolution is described here https://golang.org/pkg/net/#hdr-Name_Resolution.

By default the pure Go resolver is used, because a blocked DNS request consumes only a goroutine, while a blocked C call consumes an operating system thread. When cgo is available, the cgo-based resolver is used instead under a variety of conditions:

In the uncommon case that cgo is used, the system cache may be used. But otherwise the Go runtime explicitly does not cache DNS results. The proposal was rejected in https://github.com/golang/go/issues/24796.
 

Scope

Determine a caching policy add support for caching DNS results. Consider if this could negatively impact existing users if we change the default behavior (if so, consider making this opt-in).