From a62fd05d5392fd48a5fe9347451a49d18f564ab0 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Sat, 18 Mar 2023 11:59:01 -0500
Subject: [PATCH] perf: Reduce alloc calls when building

Inspired by #4774
---
 src/mkeymap.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/mkeymap.rs b/src/mkeymap.rs
index a54fae455c0..e9d6ab8442e 100644
--- a/src/mkeymap.rs
+++ b/src/mkeymap.rs
@@ -126,6 +126,8 @@ impl MKeyMap {
     /// We need a lazy build here since some we may change args after creating
     /// the map, you can checkout who uses `args_mut`.
     pub(crate) fn _build(&mut self) {
+        // There will be at least as many keys as args, so that is a good starting point
+        self.keys.reserve(self.args.len());
         for (i, arg) in self.args.iter().enumerate() {
             append_keys(&mut self.keys, arg, i);
         }