func WithDefaultEndpoint(url string) option.ClientOption {
	return defaultEndpointOption(url)
}
WithDefaultEndpoint is an option that indicates the default endpoint.

It should only be used internally by generated clients.

This is similar to WithEndpoint, but allows us to determine whether the user has overridden the default endpoint.
package internaloption
import (
	"google.golang.org/api/internal"
	"google.golang.org/api/option"
)
type defaultEndpointOption string
func (o defaultEndpointOption) Apply(settings *internal.DialSettings) {
	settings.DefaultEndpoint = string(o)
}