feat request: sync analog of asyncio.gather

[RomanMIzulin]

Feature request

Future containers are cool, but is not possible to concurrently execute them from sync context.

Like this

@future_safe
async def f()->Any:
  ...
@future_safe
async def g()->Any:
  ...

results = sync.gather(*[f(),g()])

[RomanMIzulin]

In Tg you said something about TaskGroups, it is related? If yes, then how?