readable yet not...

wtf.js

// something about delaying a pipe causes child process stdout to become `readable:false`
function test(prefix, delay_fn, cb) {
   var x=new (require("stream").Transform);
   x._transform = (function (chunk, enc, cb) {
     console.log(prefix, 'chunk:', chunk);
     cb(null);
   }) 
   var child=require("child_process").spawn("head", ["-c","-2"]);
   child.on('exit', function () {
     console.log('exit', prefix);
     if (cb) cb();
   })
   child.stdout.on('readable', console.log.bind(console, prefix, 'emitted readable'))
   delay_fn(function () {
     console.log(prefix, 'set to pipe(), is readable = ', child.stdout.readable)
     child.stdout.pipe(x)
   })
}     
      
test('setTimeout (100)', function (fn) {
   setTimeout(fn, 100);
})