message: [types] rename timestamp_usec to timestamp_usecs
  Closes:
  Approved by: wqfish
diff: @@ -22,7 +22,7 @@ use std::collections::BTreeMap;
  #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
  pub struct BlockMetadata {
  id: HashValue,
  - timestamp_usec: u64,
  + timestamp_usecs: u64,
  // Since Move doesn't support hashmaps, this vote map would be stored as a vector of key value
  // pairs in the Move module. Thus we need a BTreeMap here to define how the values are being
  // ordered.
  @@ -33,13 +33,13 @@ pub struct BlockMetadata {
  impl BlockMetadata {
  pub fn new(
  id: HashValue,
  - timestamp_usec: u64,
  + timestamp_usecs: u64,
  previous_block_votes: BTreeMap<AccountAddress, Ed25519Signature>,
  proposer: AccountAddress,
  ) -> Self {
  Self {
  id,
  - timestamp_usec,
  + timestamp_usecs,
  previous_block_votes,
  proposer,
  }
  @@ -48,6 +48,6 @@ impl BlockMetadata {
  pub fn into_inner(self) -> Result<(ByteArray, u64, ByteArray, AccountAddress)> {
  let id = ByteArray::new(self.id.to_vec());
  let vote_maps = ByteArray::new(lcs::to_bytes(&self.previous_block_votes)?);
  - Ok((id, self.timestamp_usec, vote_maps, self.proposer))
  + Ok((id, self.timestamp_usecs, vote_maps, self.proposer))
  }
  }
  