Play使用Bootstrap初始化服務器Channel，設置Channel類，EventLoop和Handler等。 （Play沒有使用專爲服務器準備的ServerBoostrap，而是使用更加通用的Bootstrap。這樣就可以自己安排對客戶端Channel的設置）
private def bind(address: InetSocketAddress): (Channel, Source[Channel, _]) = {
val serverChannelEventLoop = eventLoop.next
// Watches for channel events, and pushes them through a reactive streams publisher.
val channelPublisher = new HandlerPublisher(serverChannelEventLoop, classOf[Channel])
val channelClass = transport match {
case Native => classOf[EpollServerSocketChannel]
case Jdk => classOf[NioServerSocketChannel]
}
//使用Bootstrap創建服務器Channel
val bootstrap = new Bootstrap()
.channel(channelClass)
.group(serverChannelEventLoop)
.option(ChannelOption.AUTO_READ, java.lang.Boolean.FALSE) // publisher does ctx.read()
.handler(channelPublisher)
.localAddress(address)
setOptions(bootstrap.option, nettyConfig.getConfig("option"))
val channel = bootstrap.bind.await().channel()
//將服務器Channel收集到allChannels中
allChannels.add(channel)
//返回服務器Channel, 和Akka Stream Source
(channel, Source.fromPublisher(channelPublisher))
}
當有新的客戶端連接服務器時，服務器Channel上的Handler HandlerPublisher會讀取到新連接的客戶端Channel，然後將客服端Channel發佈到到Akka Stream。在Akka Stream Sink中進行客戶端Pipeline的設置和Event loop的綁定，並將所有的客戶端Channel收集到NettyServer.allChannels屬性中。
