Address review feedback

Cargo.toml

@@ -28,5 +28,12 @@ overflow-checks = true
 
 [features]
 default = []
+
+# Enables generation of DefAlloc edits for the checker.
 checker = []
-fuzzing = ["arbitrary", "checker"]
+
+# Enables detailed logging which can be somewhat expensive.
+trace-log = []
+
+# Exposes the internal API for fuzzing.
+fuzzing = ["arbitrary", "checker", "trace-log"]

src/ion/data_structures.rs

@@ -604,7 +604,7 @@ pub struct Stats {
 // the most significant field to the least significant one.
 //
 // These work best when the fields are stored in reverse order in memory so that
-// they can be loaded with a single u64 load.
+// they can be loaded with a single u64 load on little-endian machines.
 #[inline(always)]
 pub fn u64_key(b: u32, a: u32) -> u64 {
     a as u64 | (b as u64) << 32

src/lib.rs

@@ -16,7 +16,7 @@
 // performance cost so we disable it in release builds.
 macro_rules! trace {
     ($($tt:tt)*) => {
-        if cfg!(debug_assertions) {
+        if cfg!(feature = "trace-log") {
             ::log::trace!($($tt)*);
         }
     };