HTTPCLIENT-2417 Honor TlsConfig attachment in async connect path

Make PoolingAsyncClientConnectionManager.connect() use the provided TlsConfig for direct TLS connections.

(cherry picked from commit df4347f)

Author: fitekonea

httpclient5/src/main/java/org/apache/hc/client5/http/impl/nio/PoolingAsyncClientConnectionManager.java

@@ -487,14 +487,23 @@ public Future<AsyncConnectionEndpoint> connect(
         if (LOG.isDebugEnabled()) {
             LOG.debug("{} connecting endpoint to {} ({})", ConnPoolSupport.getId(endpoint), firstHop, connectTimeout);
         }
+        final Object connectAttachment;
+        if (route.isTunnelled()) {
+            connectAttachment = null;
+        } else if (attachment instanceof TlsConfig) {
+            connectAttachment = attachment;
+        } else {
+            connectAttachment = resolveTlsConfig(route.getTargetHost());
+        }
+
         final Future<ManagedAsyncClientConnection> connectFuture = connectionOperator.connect(
                 connectionInitiator,
                 firstHop,
                 unixDomainSocket,
                 route.getTargetName(),
                 route.getLocalSocketAddress(),
                 connectTimeout,
-                route.isTunnelled() ? null : resolveTlsConfig(route.getTargetHost()),
+                connectAttachment,
                 context,
                 new FutureCallback<ManagedAsyncClientConnection>() {