input := &s3.PutObjectInput{ Bucket: aws.String("my-bucket"), Key: aws.String("my-object"), Body: bytes.NewReader([]byte("hello world")), } request, _ := svc.PutObjectRequest(input) err := request.AddNested("Metadata", "author", "John Doe") if err != nil { fmt.Println(err) }This code creates an S3 PutObject request, and adds a metadata parameter called "author" with a value of "John Doe" using the AddNested method. Overall, this code is a part of the AWS SDK for Go library and is used to add nested parameters to AWS requests.