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If sender thread calls close(), it will block forever. So in if a close() we will check if the current thread is sender thread. If it iscall is called from sender thread, an error message will be logged and close(-1) will be executedput in the log and sender thread will be blocked forever. This is to:

1. Keep the current behaviour unchanged.
2. Let user to notice that something went wrong because producer does not close.

Compatibility, Deprecation, and Migration Plan

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