tErr: Future[string]], useFakePty: bool,
    closeWhenCapturesFlushed: seq[AsyncIoBase], afterSpawn: proc () {.closure.},
    afterWait: proc (): Future[void] {.closure.}]" href="_._/src/asyncproc/private/childproc_posix.html#toChildStream%2CStreamsBuilder">childproc_posix: proc toChildStream(streamsBuilder: StreamsBuilder): tuple[
    passFds: seq[tuple[src: FileHandle, dest: FileHandle]],
    captures: tuple[input, output, outputErr: Future[string]], useFakePty: bool,
    closeWhenCapturesFlushed: seq[Asy