Validate UTF-8 string before heap allocation

This avoids unnecessary heap allocation with invalid strings.

src/utils/mod.rs

@@ -67,8 +67,11 @@ pub fn u64_from_bytes(bytes: &[u8]) -> Result<u64, std::array::TryFromSliceError
 }
 
 /// Parses the bytes into a string.
-pub fn string_from_bytes(bytes: &[u8]) -> Result<String, std::string::FromUtf8Error> {
-    String::from_utf8(bytes.to_vec())
+///
+/// If `&str` is enough please use [str::from_utf8] to avoid unnecessary
+/// allocation.
+pub fn string_from_bytes(bytes: &[u8]) -> Result<String, std::str::Utf8Error> {
+    str::from_utf8(bytes).map(ToOwned::to_owned)
 }
 
 pub fn random_string(length: usize) -> String {