接连调用springboot-dubbo-seata的buy执行15次左右，就报错

2019-05-02 08:37:00.516 ERROR 5936 --- [lector_RMROLE_1] i.s.core.rpc.netty.MessageCodecHandler : decode error

java.lang.IndexOutOfBoundsException: readerIndex(56) + length(73) exceeds writerIndex(128): PooledUnsafeDirectByteBuf(ridx: 56, widx: 128, cap: 128)
at io.netty.buffer.AbstractByteBuf.checkReadableBytes0(AbstractByteBuf.java:1437) ~[netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.buffer.AbstractByteBuf.checkReadableBytes(AbstractByteBuf.java:1420) ~[netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.buffer.AbstractByteBuf.readBytes(AbstractByteBuf.java:895) ~[netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.buffer.AbstractByteBuf.readBytes(AbstractByteBuf.java:903) ~[netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.seata.core.protocol.transaction.AbstractBranchEndRequest.decode(AbstractBranchEndRequest.java:225) ~[seata-core-0.5.0.jar:na]
at io.seata.core.rpc.netty.MessageCodecHandler.decode(MessageCodecHandler.java:189) ~[seata-core-0.5.0.jar:na]
at io.netty.handler.codec.ByteToMessageCodec$1.decode(ByteToMessageCodec.java:42) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:502) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:441) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:278) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.codec.ByteToMessageCodec.channelRead(ByteToMessageCodec.java:103) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:648) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:583) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:500) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:462) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:897) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-all-4.1.31.Final.jar:4.1.31.Final]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_144]

2019-05-02 08:37:00.521 ERROR 5936 --- [lector_RMROLE_1] io.seata.core.rpc.netty.RmRpcClient : 0318

Reproduce the springboot-dubbo-seata buy call repeatedly until the decode error appears, then inspect AbstractBranchEndRequest.decode at line 225 and MessageCodecHandler.decode at line 189. Trace the seata-core 0.5.0 message handling around RmRpcClient and confirm the repeated calls no longer produce the IndexOutOfBoundsException.

Written by the indexing model from the issue text.