Motivation
Currently frontend is polling connection status as well as import progress periodically from the backend. This approach has some problems:

• if counts are coming slow from engine import progress calculation takes longer then connection timeout, therefore multiple requests from FE queue up without being effectively consumed
• each connection has overhead of handshake, etc. that can be avoided if connection is established once only

AT

• given
  • optimize is running
• when
  • I open web socket connection to get status of progress-import
• then
  • import-progress status is reported periodically

Implementation hints

• use configurable amount of threads to report status
  • once maximum is reached, close session with appropriate response message
  • write to the log, that maximum number of sessions is reached