HLS: investigate using SEEK appendbytesaction instead of RESET

[jeroen]

Here's the code from Moses. Investigate if this improves stability:

// Adaptive.as

        /** Start playing an new adaptive stream. **/
        public function play(url:String,start:Number=0):void {
            _buffer.play(url, start, _getter);
        };

// Buffer.as

        /** Create the buffer. **/
        public function Buffer(adaptive:Adaptive, loader:Loader, video:Object):void {
            _adaptive = adaptive;
            _loader = loader;
            _video = video;
            _adaptive.addEventListener(AdaptiveEvent.MANIFEST,_manifestHandler);
            _connection = new NetConnection();
            _connection.connect(null);
            _transform = new SoundTransform();
            _transform.volume = 0.9;
            _setState(AdaptiveStates.IDLE);
        };
        
        public function play(url:String, start:Number, _getter:Getter):void { // #MG
            startPosition = start;
            _stream = new NetStream(_connection);
            _video.attachNetStream(_stream);
            _stream.play(null);
            _stream.soundTransform = _transform;
            _stream.appendBytesAction(NetStreamAppendBytesAction.RESET_BEGIN);
            _stream.appendBytes(FLV.getHeader());
            _getter.load(url);
        };

        public function pause():void {
            _stream.pause();
            clearInterval(_interval);
            _setState(AdaptiveStates.PAUSED);
        };

        public function resume():void {
            _setState(AdaptiveStates.BUFFERING);
            _stream.resume();
            clearInterval(_interval);
            _interval = setInterval(_checkBuffer,100);
        };

        /** Start playing data in the buffer. **/
        public function seek(position:Number):void {
            if(_levels.length) {
                var level:Level = (_levels[_level] as Level);
                if(_adaptive.getType() == AdaptiveTypes.LIVE) {
                    position = level.duration - 20;
                } else if (position > level.duration - 1) {
                    position = level.duration - 1;
                }
                _buffer = new Vector.<Tag>();
                _start = 0;
                _tag = 0;
                _stream.inBufferSeek = true;
                _stream.seek(0); // #MG value is arbitrary. this plus RESET_SEEK flushes the FIFO buffer.
                _stream.appendBytesAction(NetStreamAppendBytesAction.RESET_SEEK);
                _next = level.indexOf(position);
                _start = level.fragments[_next].start;
                _setState(AdaptiveStates.BUFFERING);
                clearInterval(_interval);
                _interval = setInterval(_checkBuffer,100);
            }
        };

[jeroen]

Added the main fix in this patch (using RESET_SEEK instead of RESET_BEGIN for seeks in netstream).