end event no fire in readableStreambuffer

``` javascript
pngStream = new ReadableStreamBuffer
    pngStream.put buffer
    pngStream.on 'data', (chunk)->
      console.log chunk

    pngStream.on 'end', ()->
      console.log 'end'

    pngStream.on 'close', ->
      console.log 'close'
```

event end and close handler not called
