replace generic with impl T

fastfield_codecs/src/bitpacked.rs

@@ -105,8 +105,8 @@ impl FastFieldCodecSerializer for BitpackedFastFieldSerializer {
     /// It requires a `min_value` and a `max_value` to compute
     /// compute the minimum number of bits required to encode
     /// values.
-    fn serialize<W: Write>(
-        write: &mut W,
+    fn serialize(
+        write: &mut impl Write,
         _fastfield_accessor: &dyn FastFieldDataAccess,
         stats: FastFieldStats,
         data_iter: impl Iterator<Item = u64>,

fastfield_codecs/src/lib.rs

@@ -40,15 +40,13 @@ pub trait FastFieldCodecSerializer {
     /// Serializes the data using the serializer into write.
     /// There are multiple iterators, in case the codec needs to read the data multiple times.
     /// The iterators should be preferred over using fastfield_accessor for performance reasons.
-    fn serialize<W>(
-        write: &mut W,
+    fn serialize(
+        write: &mut impl Write,
         fastfield_accessor: &dyn FastFieldDataAccess,
         stats: FastFieldStats,
         data_iter: impl Iterator<Item = u64>,
         data_iter1: impl Iterator<Item = u64>,
-    ) -> io::Result<()>
-    where
-        W: Write;
+    ) -> io::Result<()>;
 }
 
 /// FastFieldDataAccess is the trait to access fast field data during serialization and estimation.

fastfield_codecs/src/linearinterpol.rs

@@ -109,16 +109,13 @@ impl FastFieldCodecSerializer for LinearInterpolFastFieldSerializer {
     const NAME: &'static str = "LinearInterpol";
     const ID: u8 = 2;
     /// Creates a new fast field serializer.
-    fn serialize<W>(
-        write: &mut W,
+    fn serialize(
+        write: &mut impl Write,
         fastfield_accessor: &dyn FastFieldDataAccess,
         stats: FastFieldStats,
         data_iter: impl Iterator<Item = u64>,
         data_iter1: impl Iterator<Item = u64>,
-    ) -> io::Result<()>
-    where
-        W: Write,
-    {
+    ) -> io::Result<()> {
         assert!(stats.min_value <= stats.max_value);
 
         let first_val = fastfield_accessor.get_val(0);

fastfield_codecs/src/multilinearinterpol.rs

@@ -194,16 +194,13 @@ impl FastFieldCodecSerializer for MultiLinearInterpolFastFieldSerializer {
     const NAME: &'static str = "MultiLinearInterpol";
     const ID: u8 = 3;
     /// Creates a new fast field serializer.
-    fn serialize<W>(
-        write: &mut W,
+    fn serialize(
+        write: &mut impl Write,
         fastfield_accessor: &dyn FastFieldDataAccess,
         stats: FastFieldStats,
         data_iter: impl Iterator<Item = u64>,
         _data_iter1: impl Iterator<Item = u64>,
-    ) -> io::Result<()>
-    where
-        W: Write,
-    {
+    ) -> io::Result<()> {
         assert!(stats.min_value <= stats.max_value);
 
         let first_val = fastfield_accessor.get_val(0);