feat(ecstore): LocalDisk writes file by spawn_blocking

ecstore/src/disk/local.rs

@@ -671,12 +671,21 @@ impl LocalDisk {
             }
         };
 
-        let data: &[u8] = match &data {
-            InternalBuf::Ref(buf) => buf,
-            InternalBuf::Owned(buf) => buf.as_ref(),
-        };
-
-        f.write_all(data).await.map_err(to_file_error)?;
+        match data {
+            InternalBuf::Ref(buf) => {
+                f.write_all(buf).await.map_err(to_file_error)?;
+            }
+            InternalBuf::Owned(buf) => {
+                // Reduce one copy by using the owned buffer directly.
+                // It may be more efficient for larger writes.
+                let mut f = f.into_std().await;
+                let task = tokio::task::spawn_blocking(move || {
+                    use std::io::Write as _;
+                    f.write_all(buf.as_ref()).map_err(to_file_error)
+                });
+                task.await??;
+            }
+        }
 
         Ok(())
     }