var stream = require('stream')
var streamEvents = require('stream-events')
var util = require('util')
function MyStream() {
  stream.Duplex.call(this)
  streamEvents.call(this)
}
util.inherits(MyStream, stream.Duplex)
MyStream.prototype._read = function(chunk) {
  console.log('_read called as usual')
  this.push(new Buffer(chunk))
  this.push(null)
}
MyStream.prototype._write = function() {
  console.log('_write called as usual')
}
var stream = new MyStream
stream.on('reading', function() {
  console.log('stream is being asked for data')
})
stream.on('writing', function() {
  console.log('stream is being sent data')
})
stream.pipe(stream)

var duplexify = require('duplexify')
var streamEvents = require('stream-events')
var fs = require('fs')
var dup = streamEvents(duplexify())
dup.on('writing', function() {
  // do something async
  dup.setWritable(/*writable stream*/)
})
fs.createReadStream('file').pipe(dup)