node.js 中的 buffer 用于处理原始二进制数据，这在处理流、文件或网络数据时非常有用。
const buf = buffer.from('hello');
const buf = buffer.alloc(10); // 10-byte buffer filled with zeros
const buf = buffer.from([72, 101, 108, 108, 111]); // represents 'hello'
const buf = buffer.from('hello');
console.log(buf.tostring()); // 'hello'
const buf = buffer.from('hello');
console.log(buf.length); // 5 (each character takes 1 byte)
const buf = buffer.alloc(5);
buf.write('hi');
console.log(buf.tostring()); // 'hi'
const buf = buffer.from('hello world');
const slice = buf.slice(null, 5);
console.log(slice.tostring()); // 'hello'
const buf1 = buffer.from('hello');
const buf2 = buffer.alloc(5);
buf1.copy(buf2);
console.log(buf2.tostring()); // 'hello'
const buf1 = buffer.from('abc');
const buf2 = buffer.from('abc');
console.log(buf1.equals(buf2)); // true
const buf1 = Buffer.from('Hello');
const buf2 = Buffer.from(' World');
const buf3 = Buffer.concat([buf1, buf2]);
console.log(buf3.toString()); // 'Hello World'
这些是开始在 node.js 中处理二进制数据时需要了解的关键 buffer 函数：
这足以处理 node.js 中的大多数初学者用例！