feat(#733)Support nginx bandwidth control

core/pkg/ingress/defaults/main.go

@@ -88,4 +88,15 @@ type Backend struct {
 	// WhitelistSourceRange allows limiting access to certain client addresses
 	// http://nginx.org/en/docs/http/ngx_http_access_module.html
 	WhitelistSourceRange []string `json:"whitelist-source-range,-"`
+
+	// Limits the rate of response transmission to a client.
+	// The rate is specified in bytes per second. The zero value disables rate limiting.
+	// The limit is set per a request, and so if a client simultaneously opens two connections,
+	// the overall rate will be twice as much as the specified limit.
+	// http://nginx.org/en/docs/http/ngx_http_core_module.html#limit_rate
+	LimitRate int `json:"limit-rate"`
+
+    // Sets the initial amount after which the further transmission of a response to a client will be rate limited.
+	// http://nginx.org/en/docs/http/ngx_http_core_module.html#limit_rate_after
+	LimitRateAfter int `json:"limit-rate-after"`
 }