Bulk stream support

[ealsur]

Pull Request Template

Description

This is the base for #584. A subsequent PR will contain the behavioral flag to leverage on the public API layer.

Bulk API Stream implementation allows for throughput optimized scenarios where the user can invoke the normal SDK APIs (Create/Update) and these will be dynamically sorted and dispatched through batches to the Bulk API without the user actively creating a batch.

There are 3 base classes and one executor implementation (operations on the same container):

• “BatchAsyncOperationContext” is the one that maintains the context for each batch operation, it has the TaskCompletionSource and ItemBatchOperation.
• “BatchAsyncBatcher” holds a batch of operations with TryAdd implementation and DispatchAsync implementation. DispatchAsync will call a Lambda executor passing it the current batch and complete the Tasks based on the outcome (Failing tasks if an exception occurred, or completing them with the expected result).
• “BatchAsyncStreamer” has the AddAsync implementation, that leverages the Batcher and will call TryAdd and DispatchAsync as the batcher fills up. It also contains a Timer that dispatches batches that are not full but within a certain period of time.
• Finally, “BatchAsyncContainerExecutor” is an implementation that handles batches for a single container, using BatchAsyncStreamers, one Streamer per PK Range. The implementation is similar to what the Friends assembly had with CrossPartitionKeyBatchExecutor, it will call AddAsync on the Streamer and pass an Execute implementation that, once the batch is signaled to be dispatched, it will leverage the PartitionKeyRangeBatchExecutor for that batch, and like the CrossPartitionKeyRangeBatchExecutor, taking into consideration possible splits.

Type of change

• New feature (non-breaking change which adds functionality)