perf: slightly optimize Vec usage

Cargo.lock

@@ -1471,6 +1471,7 @@ dependencies = [
  "ncr",
  "parking_lot",
  "serde_json",
+ "smallvec",
  "tokio",
  "zip",
 ]

Cargo.toml

@@ -36,6 +36,7 @@ mlua = { version = "0", features = ["async", "luajit", "send"] }
 ncr = { version = "0", features = ["cfb8", "ecb", "gcm"] }
 parking_lot = "0"
 serde_json = "1"
+smallvec = { version = "1", features = ["write"] }
 tokio = { version = "1", features = ["macros"] }
 zip = "2"
 

src/lua/block.rs

@@ -41,7 +41,7 @@ pub async fn get_block_states(
     lua: Lua,
     (block_names, filter_fn): (Vec<String>, Option<Function>),
 ) -> Result<Vec<u16>> {
-    let mut matched = Vec::new();
+    let mut matched = Vec::with_capacity(16);
     for block_name in block_names {
         for block in
             (u32::MIN..u32::MAX).map_while(|possible_id| BlockState::try_from(possible_id).ok())

src/lua/client/mod.rs

@@ -109,11 +109,7 @@ fn id(_lua: &Lua, client: &Client) -> Result<i32> {
 }
 
 fn tab_list(_lua: &Lua, client: &Client) -> Result<Vec<Player>> {
-    let mut tab_list = Vec::new();
-    for (_, player_info) in client.tab_list() {
-        tab_list.push(Player::from(player_info));
-    }
-    Ok(tab_list)
+    Ok(client.tab_list().into_values().map(Player::from).collect())
 }
 
 fn username(_lua: &Lua, client: &Client) -> Result<String> {

src/lua/client/world/mod.rs

@@ -56,7 +56,7 @@ pub async fn find_all_entities(
     client: UserDataRef<Client>,
     (): (),
 ) -> Result<Vec<Table>> {
-    let mut matched = Vec::new();
+    let mut matched = Vec::with_capacity(256);
     for (position, custom_name, kind, uuid, direction, id, owner_uuid, pose) in
         get_entities!(client)
     {

src/lua/player.rs

@@ -13,7 +13,7 @@ pub struct Player {
 impl From<PlayerInfo> for Player {
     fn from(p: PlayerInfo) -> Self {
         Self {
-            display_name: p.display_name.map(|n| n.to_string()),
+            display_name: p.display_name.map(|text| text.to_string()),
             gamemode: p.gamemode.to_id(),
             latency: p.latency,
             name: p.profile.name,

src/replay/mod.rs

@@ -8,6 +8,7 @@ use azalea::{
     protocol::packets::{PROTOCOL_VERSION, ProtocolPacket, VERSION_NAME},
 };
 use serde_json::json;
+use smallvec::SmallVec;
 use std::{
     fs::File,
     io::Write,
@@ -72,15 +73,16 @@ impl Recorder {
     }
 
     fn save_raw_packet(&mut self, raw_packet: &[u8]) -> Result<()> {
-        let mut data = Vec::from(self.get_timestamp()?);
-        data.extend(TryInto::<u32>::try_into(raw_packet.len())?.to_be_bytes());
+        let mut data = Vec::with_capacity(raw_packet.len() + 8);
+        data.extend(self.get_timestamp()?);
+        data.extend(&TryInto::<u32>::try_into(raw_packet.len())?.to_be_bytes());
         data.extend(raw_packet);
         self.zip_writer.write_all(&data)?;
         Ok(())
     }
 
     fn save_packet<T: ProtocolPacket>(&mut self, packet: &T) -> Result<()> {
-        let mut raw_packet = Vec::new();
+        let mut raw_packet = SmallVec::<[u8; 256]>::new();
         packet.id().azalea_write_var(&mut raw_packet)?;
         packet.write(&mut raw_packet)?;
         self.save_raw_packet(&raw_packet)