What are the purpose of the following:
batchCheckpointFrequency - 1 - The number of event batches to process before creating an EventHub cursor checkpoint.
eventProcessorOptions/maxBatchSize - 10 - The maximum event count received per receive loop.
eventProcessorOptions/prefetchCount - 300 - The default pre-fetch count used by the underlying EventProcessorHost. The minimum allowed value is 10.
