message: Add Quic batching setting to fbcode and add thrift processing code for it
  Summary:
  Match thrfit change in to fbcode. And add the processing
  code to the proxygen processor.
diff: @@ -196,7 +196,7 @@ QuicBatchingMode getQuicBatchingMode(uint32_t val);
  // default QUIC batching size - currently used only
  // by BATCHING_MODE_GSO
  -constexpr uint32_t kDefaultQuicMaxBatchSize = 64;
  +constexpr uint32_t kDefaultQuicMaxBatchSize = 16;
  // rfc6298:
  constexpr int kRttAlpha = 8;
  