message: Add debugging info to help with the failure on Windows CI.
diff: @@ -143,6 +143,7 @@ impl Mmap {
  )
  };
  if ptr.is_null() {
  + dbg!(mapping_size);
  return Err(io::Error::last_os_error().to_string());
  }
  @@ -155,6 +156,7 @@ impl Mmap {
  let ptr =
  unsafe { VirtualAlloc(ptr::null_mut(), mapping_size, MEM_RESERVE, PAGE_NOACCESS) };
  if ptr.is_null() {
  + dbg!(mapping_size);
  return Err(io::Error::last_os_error().to_string());
  }
  