Debug repro and attempt fixing rpc bug

Author: henrybear327

tests/robustness/Makefile

@@ -77,7 +77,7 @@ test-robustness-issue19179: /tmp/etcd-v3.5.17-failpoints/bin
 
 .PHONY: test-robustness-issue20573
 test-robustness-issue20573: /tmp/etcd-v3.6.4-failpoints/bin
-	GO_TEST_FLAGS='-v -run=TestRobustnessRegression/issue20573 -count 200 -failfast --bin-dir=/tmp/etcd-v3.6.4-failpoints/bin' $(TOPLEVEL_MAKE) test-robustness && \
+	GO_TEST_FLAGS='-v -run=TestRobustnessRegression/issue20573 -count 2500 -failfast --bin-dir=/tmp/etcd-v3.6.4-failpoints/bin' $(TOPLEVEL_MAKE) TIMEOUT=24h test-robustness && \
 	  echo "Failed to reproduce" || echo "Successful reproduction"
 
 # Etcd API usage by Kubernetes

tests/robustness/client/watch.go

@@ -48,7 +48,6 @@ func CollectClusterWatchEvents(ctx context.Context, param CollectClusterWatchEve
 			if err != nil {
 				return err
 			}
-			defer c.Close()
 			err = watchUntilRevision(ctx, param.Lg, c, memberMaxRevisionChan, param.Cfg)
 			reports[i] = c.Report()
 			return err
@@ -71,7 +70,6 @@ func CollectClusterWatchEvents(ctx context.Context, param CollectClusterWatchEve
 				if err != nil {
 					return err
 				}
-				defer c.Close()
 				return openWatchPeriodically(ctx, &g, c, param.BackgroundWatchConfig, finish)
 			})
 		}