matklad / once_cell

The parking_lot feature has been non-default since v1.0.0 (released 16 months ago). Docs claim it is enabled by default:

once_cell/src/lib.rs

Lines 236 to 239 in a648913

    
           //! To implement a sync flavor of `OnceCell`, this crates uses either a custom re-implementation of 
        
           //! `std::sync::Once` or `parking_lot::Mutex`. This is controlled by the `parking_lot` feature, which 
        
           //! is enabled by default. Performance is the same for both cases, but the `parking_lot` based `OnceCell<T>` 
        
           //! is smaller by up to 16 bytes.

This section also claims the parking_lot feature saves up to 16 bytes. While a companion comment in Cargo.toml claims it saves up to 2 bytes. Which one of these claims is correct?

once_cell/Cargo.toml

Lines 22 to 25 in a648913

    
           # Uses parking_lot to implement once_cell::sync::OnceCell. 
        
           # This makes not speed difference, but makes each OnceCell<T> 
        
           # for up to two bytes smaller, depending on the size of the T. 
        
           parking_lot = { version = "0.11", optional = true, default_features = false }

	//! To implement a sync flavor of `OnceCell`, this crates uses either a custom re-implementation of
	//! `std::sync::Once` or `parking_lot::Mutex`. This is controlled by the `parking_lot` feature, which
	//! is enabled by default. Performance is the same for both cases, but the `parking_lot` based `OnceCell<T>`
	//! is smaller by up to 16 bytes.

	# Uses parking_lot to implement once_cell::sync::OnceCell.
	# This makes not speed difference, but makes each OnceCell<T>
	# for up to two bytes smaller, depending on the size of the T.
	parking_lot = { version = "0.11", optional = true, default_features = false }

Documentation inconsistencies regarding parking_lot