1.长度为10的实例
var buf = new Buffer(10)
2.通过给定的数组创建
var buf = new Buffer([10,20,30,40,50])
3.通过字符串创建
var buf = new Buffer("www.csdn.net","utf-8")
utf-8 是默认的编码方式
支持以下编码："ascii", "utf8", "utf16le", "ucs2", "base64" 和 "hex"。

var buf = new Buffer(200)
var len = buf.write("www.csdn.net")
console.log("写入字节数：" + len)

buf = new Buffer(26);
for (var i = 0 ; i < 26 ; i++) {
 buf[i] = i + 97;
}

console.log( buf.toString('ascii'));    // 输出: abcdefghijklmnopqrstuvwxyz
console.log( buf.toString('ascii',0,5));  // 输出: abcde
console.log( buf.toString('utf8',0,5));  // 输出: abcde
console.log( buf.toString(undefined,0,5)); // 使用 'utf8' 编码, 并输出: abcde

var buf = new Buffer('www.runoob.com');
var json = buf.toJSON(buf);
console.log(json);

var buf = new Buffer("北京")
var buf1 = new Buffer("上海")
var buf2 = Buffer.concat([buf,buf1],12)
console.log(buf2.toString())

var buffer1 = new Buffer("AVCX")
var buffer2 = new Buffer("ACVV")

var result = buffer1.compare(buffer2)

if(result < 0) {
  console.log(buffer1 + " 在 " + buffer2 + "之前");
}else if(result == 0){
  console.log(buffer1 + " 与 " + buffer2 + "相同");
}else {
  console.log(buffer1 + " 在 " + buffer2 + "之后");
}

buf.copy(targetBuffer[, targetStart[, sourceStart[, sourceEnd]]])

var buf1 = new Buffer("beiJing")
var buf2 = new Buffer(8)
buf1.copy(buf2)
console.log("buf2 content:"+buf2.toString())

buf.slice([start[, end]])

var buf1 = new Buffer("beiJing")
var buf2 = buf1.slice(0,8)
console.log("buf2 content:"+buf2)
// beiJing

buf.length;