Reintroduce timeout and keepalive for watch requests to match client-go

This will send sends keep-alive probes to the server every 30 seconds.
These features were present prior to the 1.0 refactor but were inadvertently removed.

Fixes kubernetes-client#2127

Previous relevant issues:
- Initial issue: kubernetes-client#559
  - PR: kubernetes-client#630
- Improvement: kubernetes-client#632
  - PR: kubernetes-client#635

Author: Aurelien LABATE

src/watch.ts

@@ -40,6 +40,7 @@ export class Watch {
         const controller = new AbortController();
         requestInit.signal = controller.signal as AbortSignal;
         requestInit.method = 'GET';
+        requestInit.timeout = 30000;
 
         let doneCalled: boolean = false;
         const doneCallOnce = (err: any) => {
@@ -53,6 +54,15 @@ export class Watch {
         try {
             const response = await fetch(watchURL, requestInit);
 
+            // Enable socket keep-alive to prevent connection stalls
+            if (requestInit.agent && typeof requestInit.agent === 'object') {
+                for (const socket of Object.values(requestInit.agent.sockets).flat()) {
+                    if (socket) {
+                        socket.setKeepAlive(true, 30000);
+                    }
+                }
+            }
+
             if (response.status === 200) {
                 response.body.on('error', doneCallOnce);
                 response.body.on('close', () => doneCallOnce(null));