encode_tile: Take argument by reference

src/encode_image.rs

@@ -33,7 +33,7 @@ pub fn encode_image<W: Write>(
                     }
                 }
 
-                encode_tile::encode_tile(data, *quality, writer)?
+                encode_tile::encode_tile(&data, *quality, writer)?
             }
         }
     }

src/encode_tile.rs

@@ -3,7 +3,7 @@ use std::io::Write;
 use crate::protocol::{ProtocolWriter, ProtocolWriterResult};
 
 pub fn encode_tile<W: Write>(
-    data: [u8; 256], 
+    data: &[u8; 256], 
     quality: u8, 
     writer: &mut ProtocolWriter<W>
 ) -> ProtocolWriterResult<()> {