import ( "os" ) func readFromFile(filename string) ([]byte, error) { file, err := os.Open(filename) if err != nil { return nil, err } defer file.Close() data := make([]byte, 1024) _, err = file.Read(data) if err != nil { return nil, err } return data, nil }In this example, we use os.Open to open a file and obtain a file object. We then read 1024 bytes of data from the file into our data buffer using the Read method on the file object. Finally, we return the data buffer and close the file using the Close method on the file object. The io package is used here for ReadCloser interface. The Close method on a ReadCloser object can be used to free up resources associated with the object. For example, if you were reading data from a network socket, you would want to close the socket when you're done to avoid leaving it hanging open.