diff --git a/src/filter_plugin/mod.rs b/src/filter_plugin/mod.rs
index 245f7e3..84575b7 100644
--- a/src/filter_plugin/mod.rs
+++ b/src/filter_plugin/mod.rs
@@ -8,7 +8,7 @@ pub mod strip_ansi;
 pub mod utils;
 
 pub trait FilterPlugin: Send {
-    fn filter(&mut self, mut reader: Box<&mut dyn Read>, mut writer: Box<&mut dyn Write>) -> Result<()>;
+    fn filter(&mut self, reader: Box<&mut dyn Read>, writer: Box<&mut dyn Write>) -> Result<()>;
 }
 
 pub struct FilterChain {