Netty: ByteBuf LEAK message

ERROR [nioEventLoopGroup-2-2]  io.netty.util.ResourceLeakDetector LEAK: ByteBuf.release() was not called before it's garbage-collected. See http://netty.io/wiki/reference-counted-objects.html for more information.
Recent access records:
Created at:
        io.netty.buffer.PooledByteBufAllocator.newDirectBuffer(PooledByteBufAllocator.java:331)
        io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:185)
        io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:176)
        io.netty.buffer.AbstractByteBufAllocator.ioBuffer(AbstractByteBufAllocator.java:137)
        io.netty.channel.DefaultMaxMessagesRecvByteBufAllocator$MaxMessageHandle.allocate(DefaultMaxMessagesRecvByteBufAllocator.java:114)
        io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:147)
        io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:647)
        io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:582)
        io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:499)
        io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:461)
        io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
        io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        java.lang.Thread.run(Thread.java:748)