x-apigateway-backend-policies

含义：API网关定义的API后端策略。

作用域：Operation Object(2.0)/Operation Object(3.0)

示例：

paths:
  '/users/{userId}':
    get:
      produces:
        - "application/json"
      responses:
        default:
          description: "default response"
      x-apigateway-request-type: "public"
      x-apigateway-backend:
        type: "backend endpoint type"
      x-apigateway-backend-policies:
        - type: "backend endpoint type"
          name: "backend policy name"
          conditions: 
            - type: "equal/enum/pattern",
              value: "string",
              origin: "source/request_parameter",
              parameter_name: "string"