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In Kafka Streams, State.DISCONNECTED  will be added. When something happens unexpectedly which causes the connection to vanish, the Kafka Streams application will return State.DISCONNECTED. Please note that the difference between DISCONNECTED  and DEAD  is that KafkaStreams, when it is in its dead state, is no longer running. While in the DISCONNECTED  case, it would still be alive, but could not connect to broker.

This would also mean that a new method would be added to KafkaConsumer to allow the StreamThread to query the health of the connection.

/**
 *	@return whether or not the connection is alive
 */
public boolean isConnected();

Proposed Changes

We would query individual StreamThreads for their individual status and update the state accordingly. 

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