message: Initialize BBR pacing window to initCwnd
  Summary:
  to simplify the pacing update code, without this we have an awkward
  if/else block to cover the case where pacingWindow_ is still 0
diff: @@ -38,6 +38,8 @@ BbrCongestionController::BbrCongestionController(
  conn.udpSendPacketLen * conn.transportSettings.initCwndInMss),
  recoveryWindow_(
  conn.udpSendPacketLen * conn.transportSettings.maxCwndInMss),
  + pacingWindow_(
  + conn.udpSendPacketLen * conn.transportSettings.initCwndInMss),
  // TODO: experiment with longer window len for ack aggregation filter
  maxAckHeightFilter_(kBandwidthWindowLength, 0, 0) {}
  @@ -270,13 +272,6 @@ void BbrCongestionController::updatePacing() noexcept {
  uint64_t targetPacingWindow = bandwidthEstimate * pacingGain_ * mrtt;
  if (btlbwFound_) {
  pacingWindow_ = targetPacingWindow;
  - } else if (
  - !pacingWindow_ &&
  - conn_.lossState.mrtt != std::chrono::microseconds::max() &&
  - conn_.lossState.mrtt != 0us &&
  - conn_.lossState.mrtt >= conn_.transportSettings.pacingTimerTickInterval) {
  - pacingWindow_ = initialCwnd_;
  - mrtt = conn_.lossState.mrtt;
  } else {
  pacingWindow_ = std::max(pacingWindow_, targetPacingWindow);
  }
  