_SendWatch

def __init__(self, ws: Any, what: str, loop: asyncio.AbstractEventLoop) -> None:
    self.ws = ws
    self.what = what
    self.loop = loop
    self.mark: Optional[int] = None
    self.since: Optional[float] = None
    self.dead = False
    self.handle = loop.call_later(SEND_PROBE_SECONDS, self.probe)

def probe(self) -> None:
    """Runs while the send still waits: note progress, or give up on the socket."""
    mark = _peer_progress(self.ws)
    now = self.loop.time()
    if self.since is None or (mark is not None and (self.mark is None or mark > self.mark)):
        self.mark, self.since = mark, now
    elif now - self.since >= SEND_STALL_SECONDS:
        self.dead = True
        data_logger.warning(f"{self.what} send stalled past {SEND_STALL_SECONDS:.0f}s with "
                            "nothing taken by the client; dropping it.")
        _abort_ws(self.ws)
        return
    self.handle = self.loop.call_later(SEND_PROBE_SECONDS, self.probe)