aws-sdk-java-v2: closeEventLoopUninterruptibly Hanging on WebFlux Netty

When killing my Spring WebFlux on Netty app that uses S3AsyncClient the app hangs for 16 seconds.

Expected Behavior

Expect the server to be killed faster than 16 seconds.

Current Behavior

After timing out the following stack trace is given:

02:05:04.281 [Thread-19] ERROR s.a.a.h.n.n.NettyNioAsyncHttpClient - Unable to shutdown event loop
java.lang.RuntimeException: Shutting down Netty EventLoopGroup did not complete within 16 seconds
	at software.amazon.awssdk.http.nio.netty.NettyNioAsyncHttpClient.closeEventLoopUninterruptibly(NettyNioAsyncHttpClient.java:235)
	at software.amazon.awssdk.http.nio.netty.NettyNioAsyncHttpClient.lambda$close$2(NettyNioAsyncHttpClient.java:222)
	at software.amazon.awssdk.http.nio.netty.NettyNioAsyncHttpClient$$Lambda$1600/736839034.run(Unknown Source)
	at software.amazon.awssdk.utils.FunctionalUtils.runAndLogError(FunctionalUtils.java:40)
	at software.amazon.awssdk.http.nio.netty.NettyNioAsyncHttpClient.close(NettyNioAsyncHttpClient.java:221)
	at software.amazon.awssdk.utils.IoUtils.closeQuietly(IoUtils.java:73)
	at software.amazon.awssdk.utils.IoUtils.closeIfCloseable(IoUtils.java:90)
	at software.amazon.awssdk.utils.AttributeMap.lambda$close$0(AttributeMap.java:86)
	at software.amazon.awssdk.utils.AttributeMap$$Lambda$1596/1964394254.accept(Unknown Source)
	at java.util.HashMap$Values.forEach(HashMap.java:972)
	at software.amazon.awssdk.utils.AttributeMap.close(AttributeMap.java:86)
	at software.amazon.awssdk.core.client.config.SdkClientConfiguration.close(SdkClientConfiguration.java:79)
	at software.amazon.awssdk.core.internal.http.HttpClientDependencies.close(HttpClientDependencies.java:88)
	at software.amazon.awssdk.core.internal.http.AmazonAsyncHttpClient.close(AmazonAsyncHttpClient.java:78)
	at software.amazon.awssdk.core.client.handler.BaseAsyncClientHandler.close(BaseAsyncClientHandler.java:138)
	at software.amazon.awssdk.services.s3.DefaultS3AsyncClient.close(DefaultS3AsyncClient.java:3942)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.springframework.beans.factory.support.DisposableBeanAdapter.invokeCustomDestroyMethod(DisposableBeanAdapter.java:337)
	at org.springframework.beans.factory.support.DisposableBeanAdapter.destroy(DisposableBeanAdapter.java:271)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroyBean(DefaultSingletonBeanRegistry.java:571)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroySingleton(DefaultSingletonBeanRegistry.java:543)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.destroySingleton(DefaultListableBeanFactory.java:954)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.destroySingletons(DefaultSingletonBeanRegistry.java:504)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.destroySingletons(DefaultListableBeanFactory.java:961)
	at org.springframework.context.support.AbstractApplicationContext.destroyBeans(AbstractApplicationContext.java:1041)
	at org.springframework.context.support.AbstractApplicationContext.doClose(AbstractApplicationContext.java:1017)
	at org.springframework.context.support.AbstractApplicationContext$1.run(AbstractApplicationContext.java:937)

Steps to Reproduce (for bugs)

• Deploy any Spring WebFlux 2.0.4.RELEASE app locally
• Make a request that uses the S3AsyncClient to populate the response
• Kill the server via control + c

Your Environment

• AWS Java SDK version used: 2.5.1
• JDK version used: 1.8.0_51
• Operating System and version: MacOS High Sierra 10.13.6
• Spring version: 2.0.4.RELEASE