chore: use faster-hex instead of hex

The performance here certainly doesn't make a difference, but we
try to avoid duplicate dependencies.

gix-packetline-blocking/Cargo.toml

@@ -26,7 +26,7 @@ serde = ["dep:serde", "bstr/serde"]
 [dependencies]
 serde = { version = "1.0.114", optional = true, default-features = false, features = ["std", "derive"]}
 thiserror = "1.0.34"
-hex = "0.4.2"
+faster-hex = "0.8.0"
 bstr = { version = "1.3.0", default-features = false, features = ["std"] }
 
 document-features = { version = "0.2.0", optional = true }

gix-packetline/Cargo.toml

@@ -41,7 +41,7 @@ required-features = ["blocking-io", "maybe-async/is_sync"]
 [dependencies]
 serde = { version = "1.0.114", optional = true, default-features = false, features = ["std", "derive"]}
 thiserror = "1.0.34"
-hex = "0.4.2"
+faster-hex = "0.8.0"
 bstr = { version = "1.3.0", default-features = false, features = ["std"] }
 # async support
 futures-io = { version = "0.3.16", optional = true }

gix-packetline/src/decode.rs

@@ -72,7 +72,7 @@ pub fn hex_prefix(four_bytes: &[u8]) -> Result<PacketLineOrWantedSize<'_>, Error
     }
 
     let mut buf = [0u8; U16_HEX_BYTES / 2];
-    hex::decode_to_slice(four_bytes, &mut buf).map_err(|err| Error::HexDecode { err: err.to_string() })?;
+    faster_hex::hex_decode(four_bytes, &mut buf).map_err(|err| Error::HexDecode { err: err.to_string() })?;
     let wanted_bytes = u16::from_be_bytes(buf);
 
     if wanted_bytes == 3 {

gix-packetline/src/encode/mod.rs

@@ -22,6 +22,6 @@ pub use blocking_io::*;
 
 pub(crate) fn u16_to_hex(value: u16) -> [u8; 4] {
     let mut buf = [0u8; 4];
-    hex::encode_to_slice(value.to_be_bytes(), &mut buf).expect("two bytes to 4 hex chars never fails");
+    faster_hex::hex_encode(&value.to_be_bytes(), &mut buf).expect("two bytes to 4 hex chars never fails");
     buf
 }

gix-packetline/tests/decode/mod.rs

@@ -126,7 +126,7 @@ mod streaming {
     fn error_on_invalid_hex() {
         assert_err_display(
             streaming(b"fooo"),
-            "Failed to decode the first four hex bytes indicating the line length: Invalid character 'o' at position 1",
+            "Failed to decode the first four hex bytes indicating the line length: Invalid character",
         );
     }