use Vec::with_capacity avoid realloc mem

abci/src/application/kvstore.rs

@@ -191,7 +191,7 @@ impl Application for KeyValueStoreApp {
     }
 
     fn finalize_block(&self, request: RequestFinalizeBlock) -> ResponseFinalizeBlock {
-        let mut events = Vec::new();
+        let mut events = Vec::with_capacity(request.txs.len());
         for tx in request.txs {
             let tx = std::str::from_utf8(&tx).unwrap();
             let tx_parts = tx.split('=').collect::<Vec<&str>>();

light-client/tests/model_based.rs

@@ -710,7 +710,7 @@ mod mbt {
     }
 
     fn model_based_test_batch(batch: ApalacheTestBatch) -> Vec<(String, String)> {
-        let mut res = Vec::new();
+        let mut res = Vec::with_capacity(batch.tests.len());
         for test in batch.tests {
             let tc = ApalacheTestCase {
                 model: batch.model.clone(),

testgen/src/light_chain.rs

@@ -20,7 +20,8 @@ impl LightChain {
     // TODO: like how does someone generate a chain with different validators at each height
     pub fn default_with_length(num: u64) -> Self {
         let mut last_block = LightBlock::new_default(1);
-        let mut light_blocks: Vec<LightBlock> = vec![last_block.clone()];
+        let mut light_blocks: Vec<LightBlock> = Vec::with_capacity(num as usize);
+        light_blocks.push(last_block.clone());
 
         for _i in 2..=num {
             // add "next" light block to the vector

testgen/src/tester.rs

@@ -411,6 +411,7 @@ impl Tester {
                 match batch(path, input) {
                     None => continue,
                     Some(tests) => {
+                        res_tests.reserve_exact(tests.len());
                         for (name, input) in tests {
                             let test_path = path.to_string() + "/" + &name;
                             res_tests.push((test_path, input));

tools/rpc-probe/src/plan.rs

@@ -298,7 +298,7 @@ async fn execute_parallel_interactions(
     config: &PlanConfig,
     interaction_sets: Vec<Vec<PlannedInteraction>>,
 ) -> Result<()> {
-    let mut handles = Vec::new();
+    let mut handles = Vec::with_capacity(interaction_sets.len());
     for interactions in interaction_sets {
         let mut inner_client = client.clone();
         let inner_config = config.clone();