stream: notify user of to pipe state via 'unpipe' event.

lib/stream.js

@@ -101,6 +101,8 @@ Stream.prototype.pipe = function(dest, options) {
 
     dest.removeListener('end', cleanup);
     dest.removeListener('close', cleanup);
+
+    source.emit('unpipe', dest);
   }
 
   source.on('end', cleanup);
@@ -109,7 +111,7 @@ Stream.prototype.pipe = function(dest, options) {
   dest.on('end', cleanup);
   dest.on('close', cleanup);
 
-  dest.emit('pipe', source);
+  dest.emit('pipe', source, cleanup);
 
   // Allow for unix-like usage: A.pipe(B).pipe(C)
   return dest;