internal/grpc/dnsresolver/noop.go (5 lines of code) (raw):
package dnsresolver
import "google.golang.org/grpc/resolver"
// noopResolver does nothing. It is used when a target is not resolvable.
type noopResolver struct{}
func (noopResolver) ResolveNow(resolver.ResolveNowOptions) {}
func (noopResolver) Close() {}