A soon as you type your channels you run into composability problems as you
cannot easily wait for _either_ Channel[T1] or Channel[T2].
Rather than avoiding signals I would embrace them as a general purpose
interrupt mechanism. And an interrupt can be scheduled on a different thread.
And then I would base the entire API on top of it. This way everything is
`async` in a natural fashion. The context switches become more visible in the
code. No channels, sinks or sources required.
For example:
proc requestReadOp() =
var buf: SomeBuffer
req(url = "somefile.txt", op = fmRead, mode = Blocking, env = addr(buf),
oncomplete = proc (env: pointer, src: pointer, size: int) {.cdecl.} =
copyMem env, src, size
)
Run
This way the OS only need to provide the callback based version. Well ... I
suppose it's close enough to a traditional event loop.
