EventSources will wait for 1 tick before 'opening'. There is always the
chance that the EventSource is '.close()'ed before that tick. We
therefore check the 'readyState' before opening the EventSource
- Maintain http headers as JSON-API meta for all API requests (#4946)
- Add EventSource ready for implementing blocking queries
- EventSource project implementation to enable blocking queries for service and node listings (#5267)
- Add setting to enable/disable blocking queries (#5352)