clientv3/client.go
func (c *Client) dialWithBalancer(ep string, dopts ...grpc.DialOption) (*grpc.ClientConn, error) {
	_, host, _ := endpoint.ParseEndpoint(ep)
	target := c.resolverGroup.Target(host)
	creds := c.dialWithBalancerCreds(ep)
	return c.dial(target, creds, dopts...)
}
func (c *Client) dialWithBalancer(ep string, dopts ...grpc.DialOption) (*grpc.ClientConn, error) {
	_, host, _ := endpoint.ParseEndpoint(ep)
	target := c.resolverGroup.Target(host)
	creds := c.dialWithBalancerCreds(ep)
	return c.dial(target, creds, dopts...)
}
// dialWithBalancer dials the client's current load balanced resolver group.  The scheme of the host
// of the provided endpoint determines the scheme used for all endpoints of the client connection.