我们正在使用Spring Cloud网关将请求代理到后端系统。目前，我们发现了以下错误。有谁知道可能导致以下异常的原因？
2019-05-21 09:18:24.792 WARN An exception 'io.netty.util.internal.OutOfDirectMemoryError: failed to allocate 16777216 byte(s) of direct memory (used: 2046820359, max: 2058354688)' [enable DEBUG level for full stacktrace] was thrown by a user handler's exceptionCaught() method while handling the following exception:
io.netty.util.internal.OutOfDirectMemoryError: failed to allocate 16777216 byte(s) of direct memory (used: 2046820359, max: 2058354688)
at io.netty.util.internal.PlatformDependent.incrementMemoryCounter(PlatformDependent.java:655)
at io.netty.util.internal.PlatformDependent.allocateDirectNoCleaner(PlatformDependent.java:610)
at io.netty.buffer.PoolArena$DirectArena.allocateDirect(PoolArena.java:769)
at io.netty.buffer.PoolArena$DirectArena.newChunk(PoolArena.java:745)
at io.netty.buffer.PoolArena.allocateNormal(PoolArena.java:244)
at io.netty.buffer.PoolArena.allocate(PoolArena.java:226)
at io.netty.buffer.PoolArena.reallocate(PoolArena.java:397)
at io.netty.buffer.PooledByteBuf.capacity(PooledByteBuf.java:120)
at io.netty.buffer.AbstractByteBuf.ensureWritable0(AbstractByteBuf.java:299)
at io.netty.buffer.AbstractByteBuf.ensureWritable(AbstractByteBuf.java:278)
at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1103)
at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1096)
at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1087)
at io.netty.handler.codec.ByteToMessageDecoder$1.cumulate(ByteToMessageDecoder.java:93)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1408)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:930)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:677)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:612)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:529)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:491)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:905)
at java.lang.Thread.run(Unknown Source)
spring-boot-version： 2.1.3.RELEASE
spring-cloud-version： Greenwich.SR1
反应堆净值： 0.8.5.RELEASE