message: Derive `DataSize` for `WithDir`
diff: @@ -13,6 +13,7 @@ use std::{
  path::{Path, PathBuf},
  };
  +use datasize::DataSize;
  use lazy_static::lazy_static;
  use libc::{c_long, sysconf, _SC_PAGESIZE};
  use thiserror::Error;
  @@ -138,7 +139,7 @@ pub(crate) fn write_file<P: AsRef<Path>, B: AsRef<[u8]>>(
  /// With-directory context.
  ///
  /// Associates a type with a "working directory".
  -#[derive(Clone, Debug)]
  +#[derive(Clone, DataSize, Debug)]
  pub struct WithDir<T> {
  dir: PathBuf,
  value: T,
  