Use a StagingBelt in iced_wgpu for regular buffer uploads

wgpu/src/buffer.rs

@@ -61,12 +61,22 @@ impl<T: bytemuck::Pod> Buffer<T> {
     /// Returns the size of the written bytes.
     pub fn write(
         &mut self,
-        queue: &wgpu::Queue,
+        device: &wgpu::Device,
+        encoder: &mut wgpu::CommandEncoder,
+        belt: &mut wgpu::util::StagingBelt,
         offset: usize,
         contents: &[T],
     ) -> usize {
         let bytes: &[u8] = bytemuck::cast_slice(contents);
-        queue.write_buffer(&self.raw, offset as u64, bytes);
+
+        belt.write_buffer(
+            encoder,
+            &self.raw,
+            offset as u64,
+            (bytes.len() as u64).try_into().expect("Non-empty write"),
+            device,
+        )
+        .copy_from_slice(bytes);
 
         self.offsets.push(offset as u64);