docs: func (c *ECS) DescribeContainerInstancesRequest(input *DescribeContainerInstancesInput) (req *request.Request, output *DescribeContainerInstancesOutput) {
  	op := &request.Operation{
  		Name:       opDescribeContainerInstances,
  		HTTPMethod: "POST",
  		HTTPPath:   "/",
  	}
  
  	if input == nil {
  		input = &DescribeContainerInstancesInput{}
  	}
  
  	output = &DescribeContainerInstancesOutput{}
  	req = c.newRequest(op, input, output)
  	return
  }