Fixes #2019 - Expose HttpClientTransport in JMX.

Added missing @ManagedObject annotation to AbstractConnectorHttpClientTransport.

Also exported to JMX the "multiplexed" attribute for the FCGI transport
and the "useALPN" attribute for the HTTP/2 transport.

Signed-off-by: Simone Bordet <simone.bordet@gmail.com>

jetty-client/src/main/java/org/eclipse/jetty/client/AbstractConnectorHttpClientTransport.java

@@ -35,7 +35,9 @@ import org.eclipse.jetty.io.SocketChannelEndPoint;
 import org.eclipse.jetty.io.ssl.SslClientConnectionFactory;
 import org.eclipse.jetty.util.Promise;
 import org.eclipse.jetty.util.annotation.ManagedAttribute;
+import org.eclipse.jetty.util.annotation.ManagedObject;
 
+@ManagedObject
 public abstract class AbstractConnectorHttpClientTransport extends AbstractHttpClientTransport
 {
     private final int selectors;

jetty-fcgi/fcgi-client/src/main/java/org/eclipse/jetty/fcgi/client/http/HttpClientTransportOverFCGI.java

@@ -62,6 +62,7 @@ public class HttpClientTransportOverFCGI extends AbstractConnectorHttpClientTran
         });
     }
 
+    @ManagedAttribute(value = "Whether connections are multiplexed", readonly = true)
     public boolean isMultiplexed()
     {
         return multiplexed;

jetty-http2/http2-http-client-transport/src/main/java/org/eclipse/jetty/http2/client/http/HttpClientTransportOverHTTP2.java

@@ -68,6 +68,7 @@ public class HttpClientTransportOverHTTP2 extends AbstractHttpClientTransport
         return client.getSelectors();
     }
 
+    @ManagedAttribute(value = "Whether ALPN should be used when establishing connections")
     public boolean isUseALPN()
     {
         return useALPN;