[Event Hubs] Design and implement a buffered producer client

[chradek]

Summary

Publishing events using the EventHubProducerClient is optimized for high and consistent throughput scenarios where an application would like to assert control over collecting events into batches and the decision of when those batches are sent to Event Hubs. Developers are expected to build and manage batches according to the needs of their application, while taking into account the constraints that Event Hubs places on which events may be batched together. This allows developers to prioritize trade-offs between ensuring batch density, enforcing strict ordering of events, and publishing on a consistent and predictable schedule.

Feedback from developers has indicated that this approach quickly becomes complicated in real-world applications and demands applications bear the burden of that complexity. A frequent ask is for the Event Hubs client library to include functionality to abstract that complexity away from applications and manage batching, concurrency, and sending implicitly. Developers have let us know that they would like a higher-level type similar to the event processor, but for publishing events rather than consuming them. This is the goal for the EventHubBufferedProducerClient.

API Summary

Azure/azure-sdk#3244