You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: api_op_DescribeRouteTables.go
    path of file: ./repos/aws-sdk-go-v2/service/ec2
    
    the code of the file until where you have to start completion: // Code generated by smithy-go-codegen DO NOT EDIT.

package ec2

import (
	"context"
	"fmt"
	awsmiddleware "github.com/aws/aws-sdk-go-v2/aws/middleware"
	"github.com/aws/aws-sdk-go-v2/service/ec2/types"
	"github.com/aws/smithy-go/middleware"
	smithyhttp "github.com/aws/smithy-go/transport/http"
)

// Describes one or more of your route tables. Each subnet in your VPC must be
// associated with a route table. If a subnet is not explicitly associated with any
// route table, it is implicitly associated with the main route table. This command
// does not return the subnet ID for implicit associations. For more information,
// see Route tables (https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Route_Tables.html)
// in the Amazon VPC User Guide.
func (c *Client) DescribeRouteTables(ctx context.Context, params *DescribeRouteTablesInput, optFns ...func(*Options)) (*DescribeRouteTablesOutput, error) {
	if params == nil {
		params = &DescribeRouteTablesInput{}
	}

	result, metadata, err := c.invokeOperation(ctx, "DescribeRouteTables", params, optFns, c.addOperationDescribeRouteTablesMiddlewares)
	if err != nil {
		return nil, err
	}
    
func (c *Client) addOperationDescribeRouteTablesMiddlewares(stack *middleware.Stack, options Options) (err error) {
	if err := stack.Serialize.Add(&setOperationInputMiddleware{}, middleware.After); err != nil {
		return err
	}
	err = stack.Serialize.Add(&awsEc2query_serializeOpDescribeRouteTables{}, middleware.After)
	if err != nil {
		return err
	}
	err = stack.Deserialize.Add(&awsEc2query_deserializeOpDescribeRouteTables{}, middleware.After)
	if err != nil {
		return err
	}
	if err := addProtocolFinalizerMiddlewares(stack, options, "DescribeRouteTables"); err != nil {
		return fmt.Errorf("add protocol finalizers: %v", err)
	}

	if err = addlegacyEndpointContextSetter(stack, options); err != nil {
		return err
	}
	if err = addSetLoggerMiddleware(stack, options); err != nil {
		return err
	}
	if err = addClientRequestID(stack); err != nil {
		return err
	}
	if err = addComputeContentLength(stack); err != nil {
		return err
	}
	if err = addResolveEndpointMiddleware(stack, options); err != nil {
		return err
	}
	if err = addComputePayloadSHA256(stack); err != nil {
		return err
	}
	if err = addRetry(stack, options); err != nil {
		return err
	}
	if err = addRawResponseToMetadata(stack); err != nil {
		return err
	}
	if err = addRecordResponseTiming(stack); err != nil {
		return err
	}
	if err = addClientUserAgent(stack, options); err != nil {
		return err
	}
	if err = smithyhttp.AddErrorCloseResponseBodyMiddleware(stack); err != nil {
		return err
	}
	if err = smithyhttp.AddCloseResponseBodyMiddleware(stack); err != nil {
		return err
	}
	if err = addSetLegacyContextSigningOptionsMiddleware(stack); err != nil {
		return err
	}
	if err = stack.Initialize.Add(newServiceMetadataMiddleware_opDescribeRouteTables(options.Region), middleware.Before); err != nil {
		return err
	}
	if err = addRecursionDetection(stack); err != nil {
		return err
	}
	if err = addRequestIDRetrieverMiddleware(stack); err != nil {
		return err
	}
	if err = addResponseErrorMiddleware(stack); err != nil {
		return err
	}
	if err = addRequestResponseLogging(stack, options); err != nil {
		return err
	}
	if err = addDisableHTTPSMiddleware(stack, options); err != nil {
		return err
	}
	return nil
}