StoredOnlyCompressor feature is here, and we can now access it.

src/common.rs

@@ -315,6 +315,8 @@ pub enum Compression {
     /// the encoder can do, but is meant to emulate the `Best` setting in the `Flate2`
     /// library.
     Best,
+    /// Do no compression
+    None,
     #[deprecated(
         since = "0.17.6",
         note = "use one of the other compression levels instead, such as 'fast'"

src/encoder.rs

@@ -694,6 +694,7 @@ impl<W: Write> Writer<W> {
         let adaptive_method = self.options.adaptive_filter;
 
         let zlib_encoded = match self.info.compression {
+            Compression::None => Self::stored_only_compressor(data, in_len)?,
             Compression::Fast => {
                 let mut compressor = fdeflate::Compressor::new(std::io::Cursor::new(Vec::new()))?;
 
@@ -724,13 +725,7 @@ impl<W: Write> Writer<W> {
                     // requested by the user. Doing filtering again would only add performance
                     // cost for both encoding and subsequent decoding, without improving the
                     // compression ratio.
-                    let mut compressor =
-                        fdeflate::StoredOnlyCompressor::new(std::io::Cursor::new(Vec::new()))?;
-                    for line in data.chunks(in_len) {
-                        compressor.write_data(&[0])?;
-                        compressor.write_data(line)?;
-                    }
-                    compressor.finish()?.into_inner()
+                    Self::stored_only_compressor(data, in_len)?
                 } else {
                     compressed
                 }
@@ -817,6 +812,15 @@ impl<W: Write> Writer<W> {
         Ok(())
     }
 
+    fn stored_only_compressor(data: &[u8], in_len: usize) -> Result<Vec<u8>> {
+        let mut compressor = fdeflate::StoredOnlyCompressor::new(std::io::Cursor::new(Vec::new()))?;
+        for line in data.chunks(in_len) {
+            compressor.write_data(&[0])?;
+            compressor.write_data(line)?;
+        }
+        Ok(compressor.finish()?.into_inner())
+    }
+
     /// Set the used filter type for the following frames.
     ///
     /// The default filter is [`FilterType::Sub`] which provides a basic prediction algorithm for
@@ -1706,6 +1710,7 @@ impl Compression {
             Compression::Huffman => flate2::Compression::none(),
             #[allow(deprecated)]
             Compression::Rle => flate2::Compression::none(),
+            Compression::None => flate2::Compression::none(),
         }
     }
 }