void Filter::DownstreamCallbacks::onAboveWriteBufferHighWatermark() {
  ASSERT(!on_high_watermark_called_);
  on_high_watermark_called_ = true;
  // If downstream has too much data buffered, stop reading on the upstream connection.
  parent_.readDisableUpstream(true);
}
void Filter::DownstreamCallbacks::onAboveWriteBufferHighWatermark() {
  ASSERT(!on_high_watermark_called_);
  on_high_watermark_called_ = true;
   
  parent_.readDisableUpstream(true);
}