race condition

Nobody has claimed this yet.

It seems like you need to call `setReadable` before `setWritable`.

In my case i have a transform stream [trumpet](https://github.com/substack/node-trumpet) that I configure and initialize via an async process.

something like:

``` js
module.exports = function(opts){

var duplexStream = duplexify()
var trumpet = trumpet()

asyncInit(function(){

duplexStream.setReadable(trumpet)
duplexStream.setWritable(trumpet)

})

return duplexStream

}
```

however changing the order means causes it to break ( i think it loses all buffered data ).

``` js
duplexStream.setWritable(trumpet)
duplexStream.setReadable(trumpet)
```

Start by tracing the setReadable and setWritable calls in duplexify's async initialization path, using the trumpet transform-stream example as the reproduction. Compare both call orders and investigate whether buffered data is lost when setWritable runs first. Done means initialization works in either order without losing buffered data.

Written by the indexing model from the issue text.