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In KIP-714, the client instance ID is created by the broker which responds to a client's first GetTelemetrySubscription  RPC. In KIP-848, initially the member ID was created by the broker, but subsequently KIP-1082 changed this so that the client creates its own member ID. As a result, this KIP also changes the definition of the client instance ID so that the client creates its own UUID before it makes its initial connection to the cluster, and then it uses it for all future requests made to all brokers by that client instance. In addition, when the client makes its first GetTelemetrySubscription  request, it will also supply the client instance ID which it created. There is no need to change the behaviour of the cluster in handling client telemetry requests, it will just be the case that the Apache Kafka Java client after this KIP no longer supplies a zero client instance ID expecting the broker to calculate the ID. However, for migration purposes, the existing behaviour original behavior of KIP-714 is still supported for clients which do not yet send ClientInstanceId  in the request header.

Apart from its use in client telemetry, the addition of the client instance ID has no significance to the broker. It is being added to improve traceability and problem determination.

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The client instance ID will be calculated during the constructor of the Producer , Consumer and , ShareConsumer and Admin  implementations so there is no need to have a timeout parameter on the accessor method. The following method will be added to these interfaces:

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