[Client] Continue shutdown of client when closing producers and consu…

…mers timeout (apache#15921)

- don't return exception to caller

pulsar-client/src/main/java/org/apache/pulsar/client/impl/PulsarClientImpl.java

@@ -750,24 +750,23 @@ public CompletableFuture<Void> closeAsync() {
         FutureUtil.addTimeoutHandling(combinedFuture, Duration.ofSeconds(CLOSE_TIMEOUT_SECONDS),
                 shutdownExecutor, () -> FutureUtil.createTimeoutException("Closing producers and consumers timed out.",
                         PulsarClientImpl.class, "closeAsync"));
-        combinedFuture.whenComplete((__, t) -> new Thread(() -> {
+        combinedFuture.handle((__, t) -> {
             if (t != null) {
                 log.error("Closing producers and consumers failed. Continuing with shutdown.", t);
             }
-            shutdownExecutor.shutdownNow();
-            // All producers & consumers are now closed, we can stop the client safely
-            try {
-                shutdown();
-                closeFuture.complete(null);
+            new Thread(() -> {
+                shutdownExecutor.shutdownNow();
+                // All producers & consumers are now closed, we can stop the client safely
+                try {
+                    shutdown();
+                } catch (PulsarClientException e) {
+                    log.error("Shutdown failed. Ignoring the exception.", e);
+                }
                 state.set(State.Closed);
-            } catch (PulsarClientException e) {
-                closeFuture.completeExceptionally(e);
-            }
-        }, "pulsar-client-shutdown-thread").start()).exceptionally(exception -> {
-            closeFuture.completeExceptionally(exception);
+                closeFuture.complete(null);
+            }, "pulsar-client-shutdown-thread").start();
             return null;
         });
-
         return closeFuture;
     }