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: bearer_token_signer_adapter.go
    path of file: ./repos/aws-sdk-go-v2/internal/auth/smithy
    
    the code of the file until where you have to start completion: package smithy

import (
	"context"
	"fmt"

	"github.com/aws/smithy-go"
	"github.com/aws/smithy-go/auth"
	"github.com/aws/smithy-go/auth/bearer"
	smithyhttp "github.com/aws/smithy-go/transport/http"
)

// BearerTokenSignerAdapter adapts smithy bearer.Signer to smithy http
// auth.Signer.
type BearerTokenSignerAdapter struct
    
func (v *BearerTokenSignerAdapter) SignRequest(ctx context.Context, r *smithyhttp.Request, identity auth.Identity, _ smithy.Properties) error {
	ca, ok := identity.(*BearerTokenAdapter)
	if !ok {
		return fmt.Errorf("unexpected identity type: %T", identity)
	}

	signed, err := v.Signer.SignWithBearerToken(ctx, ca.Token, r)
	if err != nil {
		return fmt.Errorf("sign request: %w", err)
	}

	*r = *signed.(*smithyhttp.Request)
	return nil
}