fix leaking TCP connections in conformance tests

conformance/utils/roundtripper/roundtripper.go

@@ -119,6 +119,14 @@ func (d *DefaultRoundTripper) CaptureRoundTrip(request Request) (*CapturedReques
 
 	transport := &http.Transport{
 		DialContext: d.CustomDialContext,
+		// We disable keep-alives so that we don't leak established TCP connections.
+		// Leaking TCP connections is bad because we could eventually hit the
+		// threshold of maximum number of open TCP connections to a specific
+		// destination. Keep-alives are not presently utilized so disabling this has
+		// no adverse affect.
+		//
+		// Ref. https://github.com/kubernetes-sigs/gateway-api/issues/2357
+		DisableKeepAlives: true,
 	}
 	if request.Server != "" && len(request.CertPem) != 0 && len(request.KeyPem) != 0 {
 		tlsConfig, err := tlsClientConfig(request.Server, request.CertPem, request.KeyPem)