Fix race condition (also a regression of the PR 19139)#19221

Merged

ahrtr merged 3 commits intoetcd-io:mainfrom ahrtr:race-20250117

Jan 22, 2025

+68-14

Commits on Jan 21, 2025

Enhance method (*serveCtx) serve to wait for all goroutines to complete before it returns
ahrtr
committed
Ensure all goroutines created by StartEtcd to complete before closing the errc
ahrtr
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add commment to clarify the etcd shutting down workflow
ahrtr
committed