[Streaming Indexing] Enhance RestClient with a new streaming API support

[reta]

Is your feature request related to a problem? Please describe.
The RestClient does not support request / response streaming in any form but we need the mechanism to communicate with new RestActions that support this new communication style (#9071)

Describe the solution you'd like
Enhance RestClient with a new streaming API support by adding the variation of request / response interaction using reactive streams.

Describe alternatives you've considered
N/A

Additional context
See please #9071