code: func (g *Cloud) CreateAlphaRegionForwardingRule(rule *computealpha.ForwardingRule, region string) error {
  	ctx, cancel := cloud.ContextWithCallTimeout()
  	defer cancel()
  
  	mc := newForwardingRuleMetricContextWithVersion("create", region, computeAlphaVersion)
  	return mc.Observe(g.c.AlphaForwardingRules().Insert(ctx, meta.RegionalKey(rule.Name, region), rule))
  }
docs: // CreateAlphaRegionForwardingRule creates and returns an Alpha
  // forwarding fule in the given region.