fix: really don't read new frames before the previous frame has been sent. (#875)

fix feb77c4396

Signed-off-by: chujDK <1768485949@qq.com>

lib/units/device/plugins/screen/stream.js

@@ -504,9 +504,9 @@ module.exports = syrup.serial()
         frameProducer.on('readable', function next() {
           var frame = frameProducer.nextFrame()
           if (frame) {
-            Promise.settle([broadcastSet.keys().map(function(id) {
+            Promise.settle(broadcastSet.keys().map(function(id) {
               return broadcastSet.get(id).onFrame(frame)
-            })]).then(next)
+            })).then(next)
           }
           else {
             frameProducer.needFrame()