Explain not using the inner iterator in Diopser

plugins/diopser/src/lib.rs

@@ -250,9 +250,10 @@ impl Plugin for Diopser {
 
             // We get better cache locality by iterating over the filters and then over the channels
             for filter_idx in 0..self.params.filter_stages.value as usize {
-                // Because of this filter_idx outer loop we can't directly iterate over
-                // `channel_samples` as the iterator would be empty after the first loop
                 for (channel_idx, filters) in self.filters.iter_mut().enumerate() {
+                    // We can also use `channel_samples.iter_mut()`, but the compiler isn't able to
+                    // optmize that iterator away and it would add a ton of overhead over indexing
+                    // the buffer directly
                     let sample = unsafe { channel_samples.get_unchecked_mut(channel_idx) };
                     *sample = filters[filter_idx].process(*sample);
                 }