diff --git a/jetty-client/src/main/java/org/eclipse/jetty/client/LeakTrackingConnectionPool.java b/jetty-client/src/main/java/org/eclipse/jetty/client/LeakTrackingConnectionPool.java
index 20f98834699..18f39546086 100644
--- a/jetty-client/src/main/java/org/eclipse/jetty/client/LeakTrackingConnectionPool.java
+++ b/jetty-client/src/main/java/org/eclipse/jetty/client/LeakTrackingConnectionPool.java
@@ -24,7 +24,7 @@ public class LeakTrackingConnectionPool extends DuplexConnectionPool
 {
     private static final Logger LOG = LoggerFactory.getLogger(LeakTrackingConnectionPool.class);
 
-    private final LeakDetector<Connection> leakDetector = new LeakDetector<Connection>()
+    private final LeakDetector<Connection> leakDetector = new LeakDetector<>()
     {
         @Override
         protected void leaked(LeakInfo leakInfo)
@@ -35,7 +35,7 @@ public class LeakTrackingConnectionPool extends DuplexConnectionPool
 
     public LeakTrackingConnectionPool(HttpDestination destination, int maxConnections, Callback requester)
     {
-        super((HttpDestination)destination, maxConnections, requester);
+        super(destination, maxConnections, requester);
         addBean(leakDetector);
     }
 
@@ -60,7 +60,7 @@ public class LeakTrackingConnectionPool extends DuplexConnectionPool
             LOG.info("Connection {}@{} released but not acquired", connection, leakDetector.id(connection));
     }
 
-    protected void leaked(LeakDetector.LeakInfo leakInfo)
+    protected void leaked(LeakDetector<Connection>.LeakInfo leakInfo)
     {
         LOG.info("Connection {} leaked at:", leakInfo.getResourceDescription(), leakInfo.getStackFrames());
     }
diff --git a/jetty-fcgi/fcgi-server/src/test/java/org/eclipse/jetty/fcgi/server/AbstractHttpClientServerTest.java b/jetty-fcgi/fcgi-server/src/test/java/org/eclipse/jetty/fcgi/server/AbstractHttpClientServerTest.java
index 2c18f80746d..ee10b68d2c6 100644
--- a/jetty-fcgi/fcgi-server/src/test/java/org/eclipse/jetty/fcgi/server/AbstractHttpClientServerTest.java
+++ b/jetty-fcgi/fcgi-server/src/test/java/org/eclipse/jetty/fcgi/server/AbstractHttpClientServerTest.java
@@ -18,6 +18,7 @@ import java.util.concurrent.atomic.AtomicLong;
 import org.eclipse.jetty.client.HttpClient;
 import org.eclipse.jetty.client.HttpClientTransport;
 import org.eclipse.jetty.client.LeakTrackingConnectionPool;
+import org.eclipse.jetty.client.api.Connection;
 import org.eclipse.jetty.fcgi.client.http.HttpClientTransportOverFCGI;
 import org.eclipse.jetty.http.HttpScheme;
 import org.eclipse.jetty.io.ByteBufferPool;
@@ -71,7 +72,7 @@ public abstract class AbstractHttpClientServerTest
         transport.setConnectionPoolFactory(destination -> new LeakTrackingConnectionPool(destination, client.getMaxConnectionsPerDestination(), destination)
         {
             @Override
-            protected void leaked(LeakDetector.LeakInfo leakInfo)
+            protected void leaked(LeakDetector<Connection>.LeakInfo leakInfo)
             {
                 connectionLeaks.incrementAndGet();
             }
diff --git a/jetty-quic/quic-server/src/main/java/org/eclipse/jetty/quic/server/ServerQuicConnection.java b/jetty-quic/quic-server/src/main/java/org/eclipse/jetty/quic/server/ServerQuicConnection.java
index d68f161f0be..8bbb2438cab 100644
--- a/jetty-quic/quic-server/src/main/java/org/eclipse/jetty/quic/server/ServerQuicConnection.java
+++ b/jetty-quic/quic-server/src/main/java/org/eclipse/jetty/quic/server/ServerQuicConnection.java
@@ -26,7 +26,6 @@ import org.eclipse.jetty.quic.common.QuicConnection;
 import org.eclipse.jetty.quic.common.QuicSession;
 import org.eclipse.jetty.quic.quiche.QuicheConfig;
 import org.eclipse.jetty.quic.quiche.QuicheConnection;
-import org.eclipse.jetty.quic.quiche.ffi.LibQuiche;
 import org.eclipse.jetty.quic.server.internal.SimpleTokenMinter;
 import org.eclipse.jetty.quic.server.internal.SimpleTokenValidator;
 import org.eclipse.jetty.server.Connector;
@@ -70,8 +69,7 @@ public class ServerQuicConnection extends QuicConnection
         QuicheConnection quicheConnection = QuicheConnection.tryAccept(quicheConfig, new SimpleTokenValidator((InetSocketAddress)remoteAddress), cipherBuffer, remoteAddress);
         if (quicheConnection == null)
         {
-            // TODO make the buffer size configurable
-            ByteBuffer negotiationBuffer = byteBufferPool.acquire(LibQuiche.QUICHE_MIN_CLIENT_INITIAL_LEN, true);
+            ByteBuffer negotiationBuffer = byteBufferPool.acquire(getOutputBufferSize(), true);
             int pos = BufferUtil.flipToFill(negotiationBuffer);
             // TODO make the token minter configurable
             if (!QuicheConnection.negotiate(new SimpleTokenMinter((InetSocketAddress)remoteAddress), cipherBuffer, negotiationBuffer))
diff --git a/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientDemandTest.java b/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientDemandTest.java
index 96e2667c63f..3e608f113a3 100644
--- a/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientDemandTest.java
+++ b/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientDemandTest.java
@@ -126,7 +126,9 @@ public class HttpClientDemandTest extends AbstractTest<TransportScenario>
     {
         init(transport);
 
-        int bufferSize = 512;
+        // A small buffer size so the response content is
+        // read in multiple buffers, but big enough for HTTP/3.
+        int bufferSize = 1536;
         byte[] content = new byte[10 * bufferSize];
         new Random().nextBytes(content);
         scenario.startServer(new EmptyServerHandler()
@@ -140,7 +142,6 @@ public class HttpClientDemandTest extends AbstractTest<TransportScenario>
         });
         scenario.startClient(client ->
         {
-            // A small buffer size so the response content is read in multiple buffers.
             client.setByteBufferPool(new MappedByteBufferPool(bufferSize));
             client.setResponseBufferSize(bufferSize);
         });
@@ -287,7 +288,7 @@ public class HttpClientDemandTest extends AbstractTest<TransportScenario>
     {
         init(transport);
 
-        int bufferSize = 512;
+        int bufferSize = 1536;
         byte[] content = new byte[10 * bufferSize];
         new Random().nextBytes(content);
         scenario.startServer(new EmptyServerHandler()
diff --git a/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientLoadTest.java b/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientLoadTest.java
index ef6465af05a..95d604dd8f3 100644
--- a/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientLoadTest.java
+++ b/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientLoadTest.java
@@ -31,18 +31,17 @@ import javax.servlet.http.HttpServletResponse;
 
 import org.eclipse.jetty.client.HttpClientTransport;
 import org.eclipse.jetty.client.LeakTrackingConnectionPool;
+import org.eclipse.jetty.client.api.Connection;
 import org.eclipse.jetty.client.api.Request;
 import org.eclipse.jetty.client.api.Response;
 import org.eclipse.jetty.client.api.Result;
-import org.eclipse.jetty.client.http.HttpClientTransportOverHTTP;
 import org.eclipse.jetty.client.util.BytesRequestContent;
-import org.eclipse.jetty.fcgi.client.http.HttpClientTransportOverFCGI;
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.HttpHeaderValue;
 import org.eclipse.jetty.http.HttpMethod;
+import org.eclipse.jetty.http3.server.HTTP3ServerConnector;
 import org.eclipse.jetty.io.ArrayByteBufferPool;
 import org.eclipse.jetty.io.ByteBufferPool;
-import org.eclipse.jetty.io.ClientConnector;
 import org.eclipse.jetty.io.LeakTrackingByteBufferPool;
 import org.eclipse.jetty.io.MappedByteBufferPool;
 import org.eclipse.jetty.server.Connector;
@@ -368,58 +367,54 @@ public class HttpClientLoadTest extends AbstractTest<HttpClientLoadTest.LoadTran
             int selectors = Math.min(1, ProcessorUtils.availableProcessors() / 2);
             ByteBufferPool byteBufferPool = new ArrayByteBufferPool();
             byteBufferPool = new LeakTrackingByteBufferPool(byteBufferPool);
-            if (transport == Transport.UNIX_DOMAIN)
+            switch (transport)
             {
-                UnixDomainServerConnector unixSocketConnector = new UnixDomainServerConnector(server, null, null, byteBufferPool, 1, selectors, provideServerConnectionFactory(transport));
-                unixSocketConnector.setUnixDomainPath(unixDomainPath);
-                return unixSocketConnector;
+                case HTTP:
+                case HTTPS:
+                case H2C:
+                case H2:
+                case FCGI:
+                    return new ServerConnector(server, null, null, byteBufferPool, 1, selectors, provideServerConnectionFactory(transport));
+                case H3:
+                    return new HTTP3ServerConnector(server, null, null, byteBufferPool, sslContextFactory, provideServerConnectionFactory(transport));
+                case UNIX_DOMAIN:
+                    UnixDomainServerConnector unixSocketConnector = new UnixDomainServerConnector(server, null, null, byteBufferPool, 1, selectors, provideServerConnectionFactory(transport));
+                    unixSocketConnector.setUnixDomainPath(unixDomainPath);
+                    return unixSocketConnector;
+                default:
+                    throw new IllegalStateException();
             }
-            return new ServerConnector(server, null, null, byteBufferPool, 1, selectors, provideServerConnectionFactory(transport));
         }
 
         @Override
         public HttpClientTransport provideClientTransport(Transport transport, SslContextFactory.Client sslContextFactory)
         {
+            HttpClientTransport clientTransport = super.provideClientTransport(transport, sslContextFactory);
             switch (transport)
             {
                 case HTTP:
                 case HTTPS:
+                case FCGI:
                 case UNIX_DOMAIN:
                 {
-                    ClientConnector clientConnector = new ClientConnector();
-                    clientConnector.setSelectors(1);
-                    clientConnector.setSslContextFactory(sslContextFactory);
-                    HttpClientTransport clientTransport = new HttpClientTransportOverHTTP(clientConnector);
+                    // Track connection leaking only for non-multiplexed transports.
                     clientTransport.setConnectionPoolFactory(destination -> new LeakTrackingConnectionPool(destination, client.getMaxConnectionsPerDestination(), destination)
                     {
                         @Override
-                        protected void leaked(LeakDetector.LeakInfo leakInfo)
+                        protected void leaked(LeakDetector<Connection>.LeakInfo leakInfo)
                         {
                             super.leaked(leakInfo);
                             connectionLeaks.incrementAndGet();
                         }
                     });
-                    return clientTransport;
-                }
-                case FCGI:
-                {
-                    HttpClientTransport clientTransport = new HttpClientTransportOverFCGI(1, "");
-                    clientTransport.setConnectionPoolFactory(destination -> new LeakTrackingConnectionPool(destination, client.getMaxConnectionsPerDestination(), destination)
-                    {
-                        @Override
-                        protected void leaked(LeakDetector.LeakInfo leakInfo)
-                        {
-                            super.leaked(leakInfo);
-                            connectionLeaks.incrementAndGet();
-                        }
-                    });
-                    return clientTransport;
+                    break;
                 }
                 default:
                 {
-                    return super.provideClientTransport(transport, sslContextFactory);
+                    break;
                 }
             }
+            return clientTransport;
         }
     }
 }
diff --git a/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientStreamTest.java b/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientStreamTest.java
index af66f5c1780..8740a8c39c6 100644
--- a/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientStreamTest.java
+++ b/tests/test-http-client-transport/src/test/java/org/eclipse/jetty/http/client/HttpClientStreamTest.java
@@ -58,6 +58,7 @@ import org.eclipse.jetty.server.handler.AbstractHandler;
 import org.eclipse.jetty.toolchain.test.MavenTestingUtils;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.IO;
+import org.junit.jupiter.api.Assumptions;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ArgumentsSource;
 
@@ -890,6 +891,9 @@ public class HttpClientStreamTest extends AbstractTest<TransportScenario>
     @ArgumentsSource(TransportProvider.class)
     public void testUploadWithOutputStreamFailureToConnect(Transport transport) throws Exception
     {
+        // Failure to connect is based on InetSocket address failure, which Unix-Domain does not use.
+        Assumptions.assumeTrue(transport != Transport.UNIX_DOMAIN);
+
         init(transport);
 
         long connectTimeout = 1000;
@@ -972,6 +976,9 @@ public class HttpClientStreamTest extends AbstractTest<TransportScenario>
     @ArgumentsSource(TransportProvider.class)
     public void testUploadWithConnectFailureClosesStream(Transport transport) throws Exception
     {
+        // Failure to connect is based on InetSocket address failure, which Unix-Domain does not use.
+        Assumptions.assumeTrue(transport != Transport.UNIX_DOMAIN);
+
         init(transport);
 
         long connectTimeout = 1000;