title: How do I wait until my lambda function finishes processing an SQS queue?
body: <p>I add a bunch of s3 paths to SQS, and lambda automatically triggers based off the SQS queue. How would I trigger a job to run only after the queue is empty? </p>
  
  <p>This seems like a challenge because if I set it to trigger when the queue is empty, it will infinitely trigger before the job runs. If I set it to trigger if the current value is 0 and the former value is non-zero, I could have it trigger accidentally before the full job is done if it processes the first few entries really fast.</p>
  
  <p>How would I set a callback to run a lambda for when an sqs recently reached 0 entries after processing data?</p>