Integrate new minicap along with a moderate rewrite. What's currently missing is recovering from socket death.

lib/units/device/plugins/screen/util/broadcastset.js

@@ -0,0 +1,40 @@
+var util = require('util')
+
+var EventEmitter = require('eventemitter3').EventEmitter
+
+function BroadcastSet() {
+  this.set = Object.create(null)
+  this.count = 0
+}
+
+util.inherits(BroadcastSet, EventEmitter)
+
+BroadcastSet.prototype.insert = function(id, ws) {
+  if (!(id in this.set)) {
+    this.set[id] = ws
+    this.count += 1
+    this.emit('insert', id)
+    if (this.count === 1) {
+      this.emit('nonempty')
+    }
+  }
+}
+
+BroadcastSet.prototype.remove = function(id) {
+  if (id in this.set) {
+    delete this.set[id]
+    this.count -= 1
+    this.emit('remove', id)
+    if (this.count === 0) {
+      this.emit('empty')
+    }
+  }
+}
+
+BroadcastSet.prototype.each = function(fn) {
+  return Object.keys(this.set).forEach(function(id) {
+    return fn(this.set[id])
+  }, this)
+}
+
+module.exports = BroadcastSet