all: fix memory leaks

src/backends/metal.rs

@@ -46,7 +46,6 @@ use {
         ffi::{CStr, CString},
         fmt::{Debug, Formatter},
         future::pending,
-        mem,
         rc::Rc,
     },
     thiserror::Error,
@@ -293,14 +292,6 @@ struct MetalInputDevice {
     transform_matrix: Cell<Option<TransformMatrix>>,
 }
 
-impl Drop for MetalInputDevice {
-    fn drop(&mut self) {
-        if let Some(fd) = self.fd.take() {
-            mem::forget(fd);
-        }
-    }
-}
-
 #[derive(Clone)]
 enum MetalDevice {
     Input(Rc<MetalInputDevice>),