safe quard potential buffer allocation

[kares]

managed to get a Netty warning on a [buffer.release] after letting Beats send logs for a few hours :

[2021-02-02T17:54:49,050][ERROR][io.netty.util.ResourceLeakDetector][main][beats-tls] LEAK: ByteBuf.release() was not called before it's garbage-collected. See https://netty.io/wiki/reference-counted-objects.html for more information.
Recent access records: 
Created at:
	io.netty.buffer.PooledByteBufAllocator.newHeapBuffer(PooledByteBufAllocator.java:346)
	io.netty.buffer.AbstractByteBufAllocator.heapBuffer(AbstractByteBufAllocator.java:168)
	io.netty.buffer.AbstractByteBufAllocator.heapBuffer(AbstractByteBufAllocator.java:159)
	org.logstash.beats.BeatsParser.inflateCompressedFrame(BeatsParser.java:218)
	org.logstash.beats.BeatsParser.decode(BeatsParser.java:182)
	io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:501)
	io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:440)
	io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
	io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
	io.netty.channel.AbstractChannelHandlerContext.access$600(AbstractChannelHandlerContext.java:61)
	io.netty.channel.AbstractChannelHandlerContext$7.run(AbstractChannelHandlerContext.java:370)
	io.netty.util.concurrent.DefaultEventExecutor.run(DefaultEventExecutor.java:66)
	io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	java.lang.Thread.run(Thread.java:748)

... shouldn't be hard to safe-guard the buffer-allocation - what's weird that I did not find anything else around that time in the logs (would assume there must have been an exception for the incriminating buffer to not get released).

[christophercutajar]

Same happened on our environment today with logstash 7.12.0

LEAK: ByteBuf.release() was not called before it's garbage-collected. See https://netty.io/wiki/reference-counted-objects.html for more information.
Recent access records: 
Created at:
	io.netty.buffer.PooledByteBufAllocator.newDirectBuffer(PooledByteBufAllocator.java:363)
	io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:187)
	io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:173)
	io.netty.buffer.AbstractByteBufAllocator.buffer(AbstractByteBufAllocator.java:107)
	org.logstash.beats.V2Batch.<init>(V2Batch.java:12)
	org.logstash.beats.BeatsParser.decode(BeatsParser.java:66)
	io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:501)
	io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:440)
	io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
	io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
	io.netty.channel.AbstractChannelHandlerContext.access$600(AbstractChannelHandlerContext.java:61)
	io.netty.channel.AbstractChannelHandlerContext$7.run(AbstractChannelHandlerContext.java:370)
	io.netty.util.concurrent.DefaultEventExecutor.run(DefaultEventExecutor.java:66)
	io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	java.base/java.lang.Thread.run(Thread.java:834)