impl `LowerHex`/`UpperHex` for `Bytes`/`BytesMut`

src/hex.rs

+use crate::{Bytes, BytesMut};
+use std::fmt::{Formatter, LowerHex, Result, UpperHex};
+
+struct BytesRef<'a>(&'a [u8]);
+
+impl<'a> LowerHex for BytesRef<'a> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        for b in self.0 {
+            write!(f, "{:02x}", b)?;
+        }
+        Ok(())
+    }
+}
+
+impl<'a> UpperHex for BytesRef<'a> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        for b in self.0 {
+            write!(f, "{:02X}", b)?;
+        }
+        Ok(())
+    }
+}
+
+macro_rules! hex_impl {
+    ($tr:ident, $ty:ty) => {
+        impl $tr for $ty {
+            fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+                $tr::fmt(&BytesRef(self.as_ref()), f)
+            }
+        }
+    };
+}
+
+hex_impl!(LowerHex, Bytes);
+hex_impl!(LowerHex, BytesMut);
+hex_impl!(UpperHex, Bytes);
+hex_impl!(UpperHex, BytesMut);

src/lib.rs

@@ -80,6 +80,7 @@ pub use crate::buf::{
 
 mod bytes;
 mod debug;
+mod hex;
 pub use crate::bytes::{Bytes, BytesMut};
 
 // Optional Serde support