Hi Kafka Dev/Users, While running tests in `StreamThreadTest.java` in kafka/streams, I noticed the test left many lingering threads. Though the class runs `shutdown` after each test, the shutdown only executes `completeShutdown` if the StreamThread is in CREATED state. See https://github.com/apache/kafka/blob/0b11971f2c94f7aadc3fab2c51d94642065a72e5/streams/src/test/java/org/apache/kafka/streams/processor/internals/StreamThreadTest.java#L231 and https://github.com/apache/kafka/blob/0b11971f2c94f7aadc3fab2c51d94642065a72e5/streams/src/main/java/org/apache/kafka/streams/processor/internals/StreamThread.java#L1435
For example, you may run test org.apache.kafka.streams.processor.internals.StreamThreadTest#shouldNotCloseTaskProducerWhenSuspending with commit 0b11971f2c94f7aadc3fab2c51d94642065a72e5. When the test calls `thread.shutdown()`, the thread is in `PARTITIONS_REVOKED` state. Thus, `completeShutdown` is not called. The test creates three lingering threads: 2 `StateUpdater` and 1 `TaskExecutor` Is this expected behavior? Should StreamTread call `completeShutdown` in other states? Thanks, Ao
