One implementation of the io.Reader interface can be found in the bytes package. It allows a byte slice to be used as the source for a Reader. In this example the byte slice is taken from a string, but is more likely to have been read from a file or network connection.

message := []byte("Hello, playground")

reader := bytes.NewReader(message)

bs := make([]byte, 5)
n, err := reader.Read(bs)
if err != nil {
    log.Fatal(err)
}

fmt.Printf("Read %d bytes: %s", n, bs)

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