Make HTTP Keep-Alive timeout configurable for backend connections

integration/fixtures/timeout/keepalive.toml

@@ -0,0 +1,31 @@
+[global]
+checkNewVersion = false
+sendAnonymousUsage = false
+
+[log]
+level = "DEBUG"
+
+[serversTransport.forwardingTimeouts]
+  idleConnTimeout = "{{ .IdleConnTimeout }}"
+
+[entryPoints]
+  [entryPoints.web]
+  address = ":8000"
+
+[api]
+
+[providers]
+   [providers.file]
+
+[http.routers]
+  [http.routers.router1]
+    Service = "keepalive"
+    Rule = "PathPrefix(`/keepalive`)"
+
+[http.services]
+  [http.services.keepalive]
+    [http.services.keepalive.LoadBalancer]
+      passHostHeader = true
+      [[http.services.keepalive.LoadBalancer.Servers]]
+        URL = "{{ .KeepAliveServer }}"
+        Weight = 1