Crate compact_waitgroup 

A compact asynchronous WaitGroup synchronization primitive.

Usage

MonoWaitGroup

let (wg, handle) = MonoWaitGroup::new();
assert!(!wg.is_done());
std::thread::spawn(move || {
    // Long-running task
    handle.done();
});
// Wait for the task to complete
wg.await;

WaitGroup

let (wg, handle) = WaitGroup::new();
let handle_cloned = handle.clone();
assert!(!wg.is_done());
std::thread::spawn(move || {
    // Long-running task
    handle_cloned.done();
});
std::thread::spawn(move || {
    // Another long-running task
    handle.done();
});
// Wait for all tasks to complete
wg.await;

Memory Layout

This crate is designed to be extremely lightweight. The memory footprint depends on the architecture and the enabled features.

By default, MonoWaitGroup shares the same underlying memory structure as WaitGroup. However, this means MonoWaitGroup carries a usize field for reference counting of workers, which is redundant for the singly-owned MonoWorkerHandle.

Enabling the compact-mono feature changes the internal definition of MonoWaitGroup. It switches to a dedicated, stripped-down layout that removes the reference counter.

Component	Default (64-bit)	With compact-mono (64-bit)	Saving
WaitGroup	32 bytes	32 bytes	0 bytes
MonoWaitGroup	32 bytes	24 bytes	8 bytes

Note:

• Sizes include the core::task::Waker (16 bytes) and required alignment padding.
• 32 bytes is often more friendly to global memory allocators.

Structs

MonoWaitGroup

WaitGroup with a single non-clonable worker handle.

MonoWorkerHandle

Non-clonable worker handle.

WaitGroup

WaitGroup with clonable worker handles.

WorkerHandle

Clonable worker handle.