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    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
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  package org.apache.hc.core5.reactive.examples;
  
  import java.net.InetSocketAddress;
  import java.util.concurrent.Future;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.hc.core5.http.ContentType;
  import org.apache.hc.core5.http.HeaderElements;
  import org.apache.hc.core5.http.HttpConnection;
  import org.apache.hc.core5.http.HttpHeaders;
  import org.apache.hc.core5.http.HttpRequest;
  import org.apache.hc.core5.http.HttpResponse;
  import org.apache.hc.core5.http.URIScheme;
  import org.apache.hc.core5.http.impl.BasicEntityDetails;
  import org.apache.hc.core5.http.impl.Http1StreamListener;
  import org.apache.hc.core5.http.impl.bootstrap.AsyncServerBootstrap;
  import org.apache.hc.core5.http.impl.bootstrap.HttpAsyncServer;
  import org.apache.hc.core5.http.message.BasicHeader;
  import org.apache.hc.core5.http.message.BasicHttpResponse;
  import org.apache.hc.core5.http.message.RequestLine;
  import org.apache.hc.core5.http.message.StatusLine;
  import org.apache.hc.core5.io.CloseMode;
  import org.apache.hc.core5.reactive.ReactiveServerExchangeHandler;
  import org.apache.hc.core5.reactor.IOReactorConfig;
  import org.apache.hc.core5.reactor.ListenerEndpoint;
  import org.apache.hc.core5.util.TimeValue;
  
  /**
   * Example of full-duplex HTTP/1.1 message exchanges using reactive streaming. This demo server works out-of-the-box
   * with {@link ReactiveFullDuplexClientExample}; it can also be invoked interactively using telnet.
   */
  public class ReactiveFullDuplexServerExample {
      public static void main(final String[] args) throws Exception {
          int port = 8080;
          if (args.length >= 1) {
              port = Integer.parseInt(args[0]);
          }
  
          final IOReactorConfig config = IOReactorConfig.custom()
              .setSoTimeout(15, TimeUnit.SECONDS)
              .setTcpNoDelay(true)
              .build();
  
          final HttpAsyncServer server = AsyncServerBootstrap.bootstrap()
              .setIOReactorConfig(config)
              .setStreamListener(new Http1StreamListener() {
                  @Override
                  public void onRequestHead(final HttpConnection connection, final HttpRequest request) {
                      System.out.println(connection.getRemoteAddress() + " " + new RequestLine(request));
  
                  }
  
                  @Override
                  public void onResponseHead(final HttpConnection connection, final HttpResponse response) {
                      System.out.println(connection.getRemoteAddress() + " " + new StatusLine(response));
                  }
  
                  @Override
                  public void onExchangeComplete(final HttpConnection connection, final boolean keepAlive) {
                      if (keepAlive) {
                          System.out.println(connection.getRemoteAddress() + " exchange completed (connection kept alive)");
                      } else {
                          System.out.println(connection.getRemoteAddress() + " exchange completed (connection closed)");
                      }
                  }
  
              })
              .register("/echo", () -> new ReactiveServerExchangeHandler((request, entityDetails, responseChannel, context, requestBody, responseBodyFuture) -> {
                  if (new BasicHeader(HttpHeaders.EXPECT, HeaderElements.CONTINUE).equals(request.getHeader(HttpHeaders.EXPECT))) {
                      responseChannel.sendInformation(new BasicHttpResponse(100), context);
                  }
  
                  responseChannel.sendResponse(
                         new BasicHttpResponse(200),
                         new BasicEntityDetails(-1, ContentType.APPLICATION_OCTET_STREAM),
                         context);
 
                 // Simply using the request publisher as the response publisher will
                 // cause the server to echo the request body.
                 responseBodyFuture.execute(requestBody);
             }))
             .create();
 
         Runtime.getRuntime().addShutdownHook(new Thread(() -> {
             System.out.println("HTTP server shutting down");
             server.close(CloseMode.GRACEFUL);
         }));
 
         server.start();
         final Future<ListenerEndpoint> future = server.listen(new InetSocketAddress(port), URIScheme.HTTP);
         final ListenerEndpoint listenerEndpoint = future.get();
         System.out.print("Listening on " + listenerEndpoint.getAddress());
         server.awaitShutdown(TimeValue.ofDays(Long.MAX_VALUE));
     }
 }