qiniu/qetag — pull request #12 by TooBug (2014-06-09 05:11:01+00:00)
Title: Create qetag.js

测试代码：
```JavaScript
var filePath = 'testfile';
getEtag(filePath,function(eTag){
console.log('filePath',eTag);
});

var fileBuffer = require('fs').readFileSync(filePath);
getEtag(fileBuffer,function(eTag){
console.log('buffer:',eTag);
});

var fileStream = require('fs').createReadStream(filepath);
getEtag(fileStream,function(eTag){
console.log('stream:',eTag);
});
```