diff --git a/rust/src/common.rs b/rust/src/common.rs
index 7c2e4f5d4d..a8880b2c4c 100644
--- a/rust/src/common.rs
+++ b/rust/src/common.rs
@@ -106,13 +106,12 @@ pub unsafe extern "C" fn rs_cstring_free(s: *mut c_char) {
 pub fn to_hex(input: &[u8]) -> String {
     return input
         .iter()
-        .map(|b| {
+        .flat_map(|b| {
             vec![
                 char::from(HEX[(b >> 4) as usize]),
                 char::from(HEX[(b & 0xf) as usize]),
             ]
         })
-        .flatten()
         .collect();
 }