Feature request: make future-related API importable
`chronos/asyncloop` does `include ./asyncfutures2`, which means that user code cannot `import chronos/asyncfutures2` (the file would be processed twice and produce unrelated definitions). I’d like to be able to [reexport][] only the future-related stuff, without sockets and everything.

[reexport]: https://github.com/SirNickolas/asyncIters-Nim/blob/11a46af67874779478258d065f50606243741048/src/asyncIters.nim#L44