同一套接字的输入流和输出流是如何相互看到的？

import java.io.*;
import java.net.*;

public class SocketExample {
    public static void main(String[] args) {
        try (Socket socket = new Socket("example.com", 80);
             OutputStream out = socket.getOutputStream();
             InputStream in = socket.getInputStream()) {

            // 发送数据到远程主机
            String message = "GET / HTTP/1.1\r\nHost: example.com\r\n\r\n";
            out.write(message.getBytes());
            out.flush();

            // 从远程主机接收数据
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}