CheckpointStore interface

A checkpoint store stores and retrieves partition ownership information and checkpoint details for each partition in a given consumer group of an event hub instance. Users are not meant to implement an CheckpointStore. Users are expected to choose existing implementations of this interface, instantiate it, and pass it to the EventHubConsumerClient class constructor when instantiating a client. Users are not expected to use any of the methods on a checkpoint store, these are used internally by the client. Implementations of CheckpointStore can be found on npm by searching for packages with the prefix @azure/eventhub-checkpointstore-.