Realtime output

[esetnik]

Description
lavary/crunz#152

I am moving this over from lavary/crunz because it's still a needed feature for this lib.

[PabloKowalczyk]

What is your use case?

[esetnik]

We use cloudwatch for monitoring application logs coming from our docker processes. We have a large number of crunz jobs implemented that pull from sqs queues in a tight loop waiting for messages to become available on the queue. Because of the lack of realtime output we do not get any job logs for up to an hour because the job runs for a long time before terminating. It makes debugging any issues very difficult because we get no output. It also can lead to memory pressure-related issues since the entire output buffer is stored in memory and never flushed for the lifetime of the job.