Event Hubs library proposal with single client

event-hubs.js

  /*
     This proposal builds on top of what was shipped in Preview 4 of Event Hubs library
     and attempts to discard a separate notion of EPH by rolling that feature into the
     existing concept of a "consumer".

     This is mainly geared towards JS and can be tweaked for Python
     This needs serious naming re-considerations for the methods on the consumer :)
  */

  const client = new EventHubClient(connectionString, eventHubName);
  
  // Create producer to send without partitionId
  const producer = client.createProducer();

  // Create producer to send specific partition
  const producer = client.createProducer(paritionId);

  // Create consumer to receive from all partitions
  const consumer = client.createConsumer(consumerGroupName);
  
  // Create consumer to receive from all partitions with load balancing
  const consumer = client.createConsumer(consumerGroupName, partitionManager)
  
  // Create consumer to receive from specific partition
  const consumer = client.createConsumer(consumerGroupName, partitionId, eventPosition)

  // Receive with push model with message & error handler
  consumer.subscribe(onMessage, onError)
  await consumer.close(); 

  // Callbacks for setup/teardown work for each partition
  consumer.onInitializePartition = (partitionContext) => {// user code}
  consumer.onClosePartition = (partitionContext, closeReason) => {// user code}
  
  // Track last enqueued event info
  const info = consumer.lastEnqueuedEventInfo[partitionId];
  console.log(info.sequenceNumber, info.offset, info.enqueuedTime, info.retrievalTime);
    
  // checkpointing. Will throw error when no partition manager is passed
  // this might leadus into the discussion if the load balancing & checkpointing features should be split
  // so that users dealing with single partition or those not planning to have multiple instances of their app
  // have the feature of checkpointing
  await consumer.updateCheckpoint(event)
  await consumer.updateCheckpoint(offset, partitionId)

  // Custom Checkpointing requires people to provide customized partition manager & call updateCheckpoint on it
  await customizedPartitionManger.updateCheckpoint(what-ever-this-needs-to-do-checkpointing)