Source:
<code>public DefaultAsyncHttpClientConfig build() { if (nettyTimer == null) nettyTimer = newNettyTimer(this); if (cookieStore == null) <START> cookieStore = new ThreadSafeCookieStore(nettyTimer); <END> return new DefaultAsyncHttpClientConfig( followRedirect, maxRedirects, strict302Handling, compressionEnforced, userAgent, realm, maxRequestRetry, disableUrlEncodingForBoundRequests, useLaxCookieEncoder, disableZeroCopy, keepEncodingHeader, resolveProxyServerSelector(), validateResponseHeaders, aggregateWebSocketFrameFragments, enablewebSocketCompression, connectTimeout, requestTimeout, readTimeout, shutdownQuietPeriod, shutdownTimeout, keepAlive, pooledConnectionIdleTimeout, connectionPoolCleanerPeriod, connectionTtl, maxConnections, maxConnectionsPerHost, acquireFreeChannelTimeout, channelPool, connectionSemaphoreFactory, keepAliveStrategy, useOpenSsl, useInsecureTrustManager, disableHttpsEndpointIdentificationAlgorithm, handshakeTimeout, enabledProtocols, enabledCipherSuites, filterInsecureCipherSuites, sslSessionCacheSize, sslSessionTimeout, sslContext, sslEngineFactory, requestFilters.isEmpty() ? Collections.emptyList() : Collections.unmodifiableList(requestFilters), responseFilters.isEmpty() ? Collections.emptyList() : Collections.unmodifiableList(responseFilters), ioExceptionFilters.isEmpty() ? Collections.emptyList() : Collections.unmodifiableList(ioExceptionFilters), cookieStore, tcpNoDelay, soReuseAddress, soKeepAlive, soLinger, soSndBuf, soRcvBuf, threadPoolName, httpClientCodecMaxInitialLineLength, httpClientCodecMaxHeaderSize, httpClientCodecMaxChunkSize, httpClientCodecInitialBufferSize, chunkedFileChunkSize, webSocketMaxBufferSize, webSocketMaxFrameSize, channelOptions.isEmpty() ? Collections.emptyMap() : Collections.unmodifiableMap(channelOptions), eventLoopGroup, useNativeTransport, allocator, nettyTimer, threadFactory, httpAdditionalChannelInitializer, wsAdditionalChannelInitializer, responseBodyPartFactory, ioThreadsCount); }</code><technical_language>This a slight behavior change: longer disable CookieStore, providing a noop implementation. existing if (cookieStore != null) guards useless</technical_language>

Target:
public DefaultAsyncHttpClientConfig build() { return new DefaultAsyncHttpClientConfig( followRedirect, maxRedirects, strict302Handling, compressionEnforced, userAgent, realm, maxRequestRetry, disableUrlEncodingForBoundRequests, useLaxCookieEncoder, disableZeroCopy, keepEncodingHeader, resolveProxyServerSelector(), validateResponseHeaders, aggregateWebSocketFrameFragments, enablewebSocketCompression, connectTimeout, requestTimeout, readTimeout, shutdownQuietPeriod, shutdownTimeout, keepAlive, pooledConnectionIdleTimeout, connectionPoolCleanerPeriod, connectionTtl, maxConnections, maxConnectionsPerHost, acquireFreeChannelTimeout, channelPool, connectionSemaphoreFactory, keepAliveStrategy, useOpenSsl, useInsecureTrustManager, disableHttpsEndpointIdentificationAlgorithm, handshakeTimeout, enabledProtocols, enabledCipherSuites, filterInsecureCipherSuites, sslSessionCacheSize, sslSessionTimeout, sslContext, sslEngineFactory, requestFilters.isEmpty() ? Collections.emptyList() : Collections.unmodifiableList(requestFilters), responseFilters.isEmpty() ? Collections.emptyList() : Collections.unmodifiableList(responseFilters), ioExceptionFilters.isEmpty() ? Collections.emptyList() : Collections.unmodifiableList(ioExceptionFilters), cookieStore, expiredCookieEvictionDelay, tcpNoDelay, soReuseAddress, soKeepAlive, soLinger, soSndBuf, soRcvBuf, threadPoolName, httpClientCodecMaxInitialLineLength, httpClientCodecMaxHeaderSize, httpClientCodecMaxChunkSize, httpClientCodecInitialBufferSize, chunkedFileChunkSize, webSocketMaxBufferSize, webSocketMaxFrameSize, channelOptions.isEmpty() ? Collections.emptyMap() : Collections.unmodifiableMap(channelOptions), eventLoopGroup, useNativeTransport, allocator, nettyTimer, threadFactory, httpAdditionalChannelInitializer, wsAdditionalChannelInitializer, responseBodyPartFactory, ioThreadsCount, hashedWheelTickDuration, hashedWheelSize); }