The following features will be included in next releases.
    
- 
          Add some minor features, in particular
          - 
                #7589
                Synchro: Add polymorphic lockables.
              
 
- 
          Add some features based on C++ proposals, in particular
          
- 
                #8273
                Synchro: Add externally locked streams.
              
- 
                #8514
                Async: Add a thread_pool executor with work stealing.
              
 
- 
          And some additional extensions related to futures as:
          - 
                #8517
                Async: Add a variadic shared_future::then.