fix warning for unused output_channel and format

src/coefficient.rs

@@ -94,34 +94,34 @@ where
                 || *channel == Channel::FrontLeft
                 || *channel == Channel::FrontRight;
         }
-         let coefficient_matrix = if only_stereo_or_discrete  && output_channels.len() >2 && input_channels.len() <= output_channels.len() {
+        let coefficient_matrix = if only_stereo_or_discrete
+            && output_channels.len() > 2
+            && input_channels.len() <= output_channels.len()
+        {
             let mut matrix = Vec::with_capacity(output_channels.len());
-            let mut idx = 0;
             // Create a diagonal line of 1.0 for input channels
-            for output_channel in output_channels {
-                let output_channel_index = idx;
-                idx+=1;
+            for (output_channel_index, _) in output_channels.iter().enumerate() {
                 let mut coefficients = Vec::with_capacity(input_channels.len());
                 coefficients.resize(input_channels.len(), 0.0);
                 if output_channel_index < coefficients.len() {
                     coefficients[output_channel_index] = 1.0;
                 }
                 matrix.push(coefficients);
             }
-          matrix
+            matrix
         } else {
-            let mixing_matrix = Self::build_mixing_matrix(input_layout.channel_map, output_layout.channel_map)
-                .unwrap_or_else(|_| Self::get_basic_matrix());
+            let mixing_matrix =
+                Self::build_mixing_matrix(input_layout.channel_map, output_layout.channel_map)
+                    .unwrap_or_else(|_| Self::get_basic_matrix());
             Self::pick_coefficients(
                 &input_layout.channels,
                 &output_layout.channels,
                 &mixing_matrix,
             )
         };
-        
+
         println!("coeffs {:?}", coefficient_matrix);
 
-
         for row in coefficient_matrix.iter() {
             println!("{:?}", row);
         }