async mode
- ensures that every request is fast, ~600ms currently, up to 60s before
- compatible with <1.1.0 api when no async is used
- reduces load on dispatcher by queueing requests
- asyncs slow and fast backends as well postprocessing
- helps to send many queries at once fast - works well with async api to submit batches of jobs
- helps to retrieve many queries at once fast - to retrieve batches of results. TODO: sometimes transport is still slow, limiting?