@SuppressWarnings("nullness") // safe because we pass sort() a range that contains real Ts
    T[] castBuffer = (T[]) buffer;
    sort(castBuffer, 0, bufferSize, comparator);
    if (bufferSize > k) {
      Arrays.fill(buffer, k, buffer.length, null);
      bufferSize = k;
      threshold = buffer[k - 1];
    }
    // Up to bufferSize, all elements of buffer are real Ts (not null unless T includes null)

        )
        return
      }

      // This is a long-lived response. Cancel full-call timeouts.
      call?.timeout()?.cancel()

      // Replace the body with a stripped one so the callbacks can't see real data.
      val response = response.stripBody()

      val reader = ServerSentEventReader(body.source(), this)
      try {
        if (!canceled) {
          listener.onOpen(this, response)