perf(cli): use faster_hex (#22761)

`cli::util::checksum` was showing up on flame graphs because it was
concatenating allocated strings. We can use `faster-hex` to improve it.

1 files changed, 2 insertions, 7 deletions

diff --git a/cli/util/checksum.rs b/cli/util/checksum.rs
index d9480eb6e..c9c55ec2b 100644
--- a/cli/util/checksum.rs
+++ b/cli/util/checksum.rs
@@ -3,18 +3,13 @@
 use ring::digest::Context;
 use ring::digest::SHA256;
 
+/// Generate a SHA256 checksum of a slice of byte-slice-like things.
 pub fn gen(v: &[impl AsRef<[u8]>]) -> String {
   let mut ctx = Context::new(&SHA256);
   for src in v {
     ctx.update(src.as_ref());
   }
-  let digest = ctx.finish();
-  let out: Vec<String> = digest
-    .as_ref()
-    .iter()
-    .map(|byte| format!("{byte:02x}"))
-    .collect();
-  out.join("")
+  faster_hex::hex_string(ctx.finish().as_ref())
 }
 
 #[cfg(test)]