feat: add copy_contents_uninit to ArrayBufferView (#1872)

add copy_contents_uninit

Author: nathanwhit

src/array_buffer_view.rs

@@ -8,6 +8,7 @@ use crate::scope::PinScope;
 use crate::support::int;
 use std::convert::TryInto;
 use std::ffi::c_void;
+use std::mem::MaybeUninit;
 
 unsafe extern "C" {
   fn v8__ArrayBufferView__Buffer(
@@ -93,6 +94,21 @@ impl ArrayBufferView {
     }
   }
 
+  /// Copy the contents of the ArrayBufferView's buffer to an embedder defined
+  /// memory without additional overhead that calling ArrayBufferView::Buffer
+  /// might incur.
+  /// Returns the number of bytes actually written.
+  #[inline(always)]
+  pub fn copy_contents_uninit(&self, dest: &mut [MaybeUninit<u8>]) -> usize {
+    unsafe {
+      v8__ArrayBufferView__CopyContents(
+        self,
+        dest.as_mut_ptr() as *mut c_void,
+        dest.len().try_into().unwrap(),
+      )
+    }
+  }
+
   /// Returns the contents of the ArrayBufferView's buffer as a MemorySpan. If
   /// the contents are on the V8 heap, they get copied into `storage`. Otherwise
   /// a view into the off-heap backing store is returned. The provided storage