message: Missing license header
diff: +/*
  + * Copyright (c) Meta Platforms, Inc. and affiliates.
  + *
  + * This source code is licensed under both the MIT license found in the
  + * LICENSE-MIT file in the root directory of this source tree and the Apache
  + * License, Version 2.0 found in the LICENSE-APACHE file in the root directory
  + * of this source tree.
  + */
  +
  use std::mem;
  /// Approximate allocated memory for hashbrown `RawTable`.
  