http: support generic Duplex streams

Support generic `Duplex` streams through more duck typing
on the server and client sides.

Since HTTP is, as a protocol, independent of its underlying transport
layer, Node.js should not enforce any restrictions on what streams
its HTTP parser may use.

Ref: https://github.com/nodejs/node/issues/16256
PR-URL: https://github.com/nodejs/node/pull/16267
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

lib/_http_server.js

@@ -303,7 +303,7 @@ function connectionListener(socket) {
   // If the user has added a listener to the server,
   // request, or response, then it's their responsibility.
   // otherwise, destroy on timeout by default
-  if (this.timeout)
+  if (this.timeout && typeof socket.setTimeout === 'function')
     socket.setTimeout(this.timeout);
   socket.on('timeout', socketOnTimeout);
 
@@ -354,11 +354,13 @@ function connectionListener(socket) {
   socket.on = socketOnWrap;
 
   // We only consume the socket if it has never been consumed before.
-  var external = socket._handle._externalStream;
-  if (!socket._handle._consumed && external) {
-    parser._consumed = true;
-    socket._handle._consumed = true;
-    parser.consume(external);
+  if (socket._handle) {
+    var external = socket._handle._externalStream;
+    if (!socket._handle._consumed && external) {
+      parser._consumed = true;
+      socket._handle._consumed = true;
+      parser.consume(external);
+    }
   }
   parser[kOnExecute] =
     onParserExecute.bind(undefined, this, socket, parser, state);
@@ -533,9 +535,13 @@ function resOnFinish(req, res, socket, state, server) {
   res.detachSocket(socket);
 
   if (res._last) {
-    socket.destroySoon();
+    if (typeof socket.destroySoon === 'function') {
+      socket.destroySoon();
+    } else {
+      socket.end();
+    }
   } else if (state.outgoing.length === 0) {
-    if (server.keepAliveTimeout) {
+    if (server.keepAliveTimeout && typeof socket.setTimeout === 'function') {
       socket.setTimeout(0);
       socket.setTimeout(server.keepAliveTimeout);
       state.keepAliveTimeoutSet = true;