v6.1.1

• Feat: Cap the size of the output buffer (max-queued-writes setting) to
  avoid out-of-memory issues. Kafka consumers are paused until the buffer
  usage falls below a fixed threshold.
• Fix: Honour hdf-output-prefix setting even if absolute paths are sent in
  pl72 messages.
• Adding (tcp based) service api to query a filewriter for its status
• Added new module 'mdat' for processing filewriter metadata
  It writes start_time and end_time automatically to the /entry.
• Fix: Cannot import extra modules due to mismatch in ep00, ep01 and al00 registered names
• Fix: Max/min/avg datasets do not specify units
• Fix: Error responses to run_stop commands are generated only if service_id is set and
  matches the id of the filewriter.
• Feat(monitoring): Export worker_state Carbon metric (idle/writing)
• Fix: EPICS alarm severity and connection status should be written as integers, not strings.