refactor: remove unused create() method from MetaPlugin trait

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/meta_plugin.rs

@@ -49,7 +49,6 @@ pub trait MetaPlugin {
         false
     }
     
-    fn create(&self) -> Result<Box<dyn Write>>;
     fn finalize(&mut self) -> io::Result<String>;
 
     // Update the meta plugin with new data

src/meta_plugin/digest.rs

@@ -26,12 +26,6 @@ impl MetaPlugin for DigestSha256MetaPlugin {
         true
     }
     
-    fn create(&self) -> Result<Box<dyn Write>> {
-        // For meta plugins, we don't actually create a writer since we're buffering data internally
-        // This method is required by the trait but not used in the same way as digest engines
-        Ok(Box::new(DummyWriter))
-    }
-
     fn finalize(&mut self) -> io::Result<String> {
         let result = self.hasher.clone().finalize();
         Ok(format!("{:x}", result))
@@ -46,19 +40,6 @@ impl MetaPlugin for DigestSha256MetaPlugin {
     }
 }
 
-// Dummy writer that implements Write but doesn't do anything
-// This is needed to satisfy the MetaPlugin trait requirements
-struct DummyWriter;
-
-impl Write for DummyWriter {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        Ok(buf.len())
-    }
-
-    fn flush(&mut self) -> io::Result<()> {
-        Ok(())
-    }
-}
 
 #[derive(Debug, Clone, Default)]
 pub struct ReadTimeMetaPlugin {
@@ -80,11 +61,6 @@ impl MetaPlugin for ReadTimeMetaPlugin {
         true
     }
     
-    fn create(&self) -> Result<Box<dyn Write>> {
-        // For meta plugins, we don't actually create a writer since we're buffering data internally
-        Ok(Box::new(DummyWriter))
-    }
-
     fn finalize(&mut self) -> io::Result<String> {
         if let Some(start_time) = self.start_time {
             let duration = start_time.elapsed();
@@ -127,11 +103,6 @@ impl MetaPlugin for ReadRateMetaPlugin {
         true
     }
     
-    fn create(&self) -> Result<Box<dyn Write>> {
-        // For meta plugins, we don't actually create a writer since we're buffering data internally
-        Ok(Box::new(DummyWriter))
-    }
-
     fn finalize(&mut self) -> io::Result<String> {
         if let Some(start_time) = self.start_time {
             let duration = start_time.elapsed();