message: [state sync] tune libra channel
  Closes:
  Approved by: christinacelee
diff: @@ -10,7 +10,7 @@ use network::{
  error::NetworkError,
  peer_manager::{ConnectionRequestSender, PeerManagerRequestSender},
  protocols::network::{NetworkEvents, NetworkSender},
  - validator_network::network_builder::{NetworkBuilder, NETWORK_CHANNEL_SIZE},
  + validator_network::network_builder::NetworkBuilder,
  ProtocolId,
  };
  use serde::{Deserialize, Serialize};
  @@ -50,8 +50,8 @@ pub fn add_to_network(
  .add_protocol_handler(
  vec![],
  vec![ProtocolId::StateSynchronizerDirectSend],
  - QueueStyle::FIFO,
  - NETWORK_CHANNEL_SIZE,
  + QueueStyle::LIFO,
  + 1,
  Some(&counters::PENDING_STATE_SYNCHRONIZER_NETWORK_EVENTS),
  );
  (
  