I think we can probably delete the call to release() entirely, but without the change I git this error thrown when the SPDY connection is closed:

io.netty.channel.NoSuchBufferException: the handler 'spdySessionHandler' has no inbound byte buffer; it does not implement ChannelInboundByteHandler.
	at io.netty.channel.DefaultChannelHandlerContext.inboundByteBuffer(DefaultChannelHandlerContext.java:450)
	at io.netty.handler.codec.spdy.SpdySessionHandler.freeInboundBuffer(SpdySessionHandler.java:95)
	at io.netty.channel.DefaultChannelHandlerContext.invokeFreeInboundBuffer0(DefaultChannelHandlerContext.java:1473)
	at io.netty.channel.DefaultChannelHandlerContext.invokeFreeInboundBuffer(DefaultChannelHandlerContext.java:1456)
	at io.netty.channel.DefaultChannelHandlerContext.invokeFreeInboundBuffer0(DefaultChannelHandlerContext.java:1483)
	at io.netty.channel.DefaultChannelHandlerContext.invokeFreeInboundBuffer(DefaultChannelHandlerContext.java:1456)
	at io.netty.channel.DefaultChannelHandlerContext.invokeFreeInboundBuffer0(DefaultChannelHandlerContext.java:1483)
	at io.netty.channel.DefaultChannelHandlerContext.invokeFreeInboundBuffer(DefaultChannelHandlerContext.java:1456)
	at io.netty.channel.DefaultChannelHandlerContext.invokeFreeInboundBuffer0(DefaultChannelHandlerContext.java:1483)
	at io.netty.channel.DefaultChannelHandlerContext.access$3100(DefaultChannelHandlerContext.java:38)
	at io.netty.channel.DefaultChannelHandlerContext$21.run(DefaultChannelHandlerContext.java:1462)
	at io.netty.channel.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:259)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:305)
	at io.netty.channel.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:110)
	at java.lang.Thread.run(Thread.java:722)