Starts or resumes the generator, running until it reaches a
        yield point that is not ready.

def run(self) -> None:
        """Starts or resumes the generator, running until it reaches a
        yield point that is not ready.
        """
        if self.running or self.finished:
            return
        try:
            self.running = True
            while True:
                future = self.future
                if future is None:
                    raise Exception("No pending future")
                if not future.done():
                    return
                self.future = None
                try:
                    exc_info = None

                    try:
                        value = future.result()
                    except Exception:
                        exc_info = sys.exc_info()
                    future = None

                    if exc_info is not None:
                        try:
                            yielded = self.gen.throw(*exc_info)  # type: ignore
                        finally:
                            # Break up a reference to itself
                            # for faster GC on CPython.
                            exc_info = None
                    else:
                        yielded = self.gen.send(value)

                except (StopIteration, Return) as e:
                    self.finished = True
                    self.future = _null_future
                    future_set_result_unless_cancelled(
                        self.result_future, _value_from_stopiteration(e)
                    )
                    self.result_future = None  # type: ignore
                    return
                except Exception:
                    self.finished = True
                    self.future = _null_future
                    future_set_exc_info(self.result_future, sys.exc_info())
                    self.result_future = None  # type: ignore
                    return
                if not self.handle_yield(yielded):
                    return
                yielded = None
        finally:
            self.running = False