Keep better track of vital streams. Add monkey.

lib/util/vitals.js

@@ -0,0 +1,24 @@
+var events = require('events')
+var util = require('util')
+
+function Vitals() {
+  events.EventEmitter.call(this)
+}
+
+util.inherits(Vitals, events.EventEmitter)
+
+Vitals.prototype.register = function(name, stream) {
+  var that = this
+
+  stream.on('end', function() {
+    that.emit('end', name)
+  })
+
+  stream.on('error', function(err) {
+    that.emit('error', name, err)
+  })
+
+  return stream
+}
+
+module.exports = Vitals