message: Add clarifying comments for store() / load() module size return value
diff: @@ -64,6 +64,8 @@ impl FileSystemCache {
  /// Loads a serialized module from the file system and returns a module (i.e. artifact + store),
  /// along with the size of the serialized module.
  + /// The serialized module size is a good approximation (~100.06 %) of the in-memory module size.
  + /// It should not be considered as the exact in-memory module size.
  pub fn load(&self, checksum: &Checksum, store: &Store) -> VmResult<Option<(Module, usize)>> {
  let filename = checksum.to_hex();
  let file_path = self.latest_modules_path().join(filename);
  @@ -93,6 +95,9 @@ impl FileSystemCache {
  }
  }
  + /// Stores a serialized module to the file system. Returns the size of the serialized module.
  + /// The serialized module size is a good approximation (~100.06 %) of the in-memory module size.
  + /// It should not be considered as the exact in-memory module size.
  pub fn store(&mut self, checksum: &Checksum, module: &Module) -> VmResult<usize> {
  let modules_dir = self.latest_modules_path();
  fs::create_dir_all(&modules_dir)
  