How to use the @azure/eventhubs-checkpointstore-blob.BlobCheckpointStore function in @azure/eventhubs-checkpointstore-blob

export async function main() {
  console.log(`Running receiveEventsUsingCheckpointStore sample`);

  // this client will be used by our eventhubs-checkpointstore-blob, which 
  // persists any checkpoints from this session in Azure Storage
  const containerClient = new ContainerClient(storageConnectionString, containerName);

  if (!(await containerClient.exists())) {
    await containerClient.create();
  }

  const checkpointStore : CheckpointStore = new BlobCheckpointStore(containerClient);

  const consumerClient = new EventHubConsumerClient(consumerGroup, connectionString, eventHubName, checkpointStore);
   
  const subscription = consumerClient.subscribe({
      processEvents: async (events, context) => {
        for (const event of events) {
          console.log(`Received event: '${event.body}' from partition: '${context.partitionId}' and consumer group: '${context.consumerGroup}'`);
        }
    
        try {
          // save a checkpoint for the last event now that we've processed this batch.
          await context.updateCheckpoint(events[events.length - 1]);
        } catch (err) {
          console.log(`Error when checkpointing on partition ${context.partitionId}: `, err);
          throw err;
        };