feat: Add support for HTTP keep-alive between the proxy and upstream

test/test_keepalive.yml

@@ -0,0 +1,25 @@
+keepalive-disabled:
+  image: web
+  expose:
+    - "80"
+  environment:
+    WEB_PORTS: 80
+    VIRTUAL_HOST: keepalive-disabled.nginx-proxy.test
+
+keepalive-enabled:
+  image: web
+  expose:
+    - "80"
+  environment:
+    WEB_PORTS: 80
+    VIRTUAL_HOST: keepalive-enabled.nginx-proxy.test
+  labels:
+    com.github.nginx-proxy.nginx-proxy.keepalive: "64"
+
+
+sut:
+  image: nginxproxy/nginx-proxy:test
+  volumes:
+    - /var/run/docker.sock:/tmp/docker.sock:ro
+  environment:
+    HTTPS_METHOD: nohttps