feat: add task group

CHANGELOG.md

@@ -26,6 +26,7 @@ All notable changes to this project will be documented in this file.
 ### New features
 
 * Implement `broadcast::mpmc::bounded`, a lossless bounded broadcast channel that retains at most the requested capacity and makes producers wait for the slowest active receiver.
+* Add an opt-in runtime-agnostic `TaskGroup` with cloneable registration handles, explicit closing, completion-ordered output consumption, and whole-group waiting and collection.
 * Add opt-in bounded and unbounded `asyncband::mpmc` queues with cloneable producers and competing consumers, delivering each accepted value to exactly one receiver while a receiver remains.
 * Add an opt-in runtime-agnostic `Phaser` with shared observer handles, dynamic RAII participants registered individually or in batches through an owning iterator, `u64` phase numbers, split arrival/wait with cancellation-resilient retries, and a `close` operation that releases unfinished waits with `Closed`.
 * Add bounded MPSC `reserve` and `try_reserve` methods returning a `Permit`, allowing callers to wait for capacity before constructing a message; pending sends and reservations receive capacity in wait-queue order, and unused permits release capacity without claiming message order.

README.md

@@ -92,6 +92,7 @@ Runnable examples live in the [`examples`](examples) workspace crate. They demon
 |                            | [`Latch`](https://docs.rs/asyncband/*/asyncband/latch/struct.Latch.html)                       | `latch`        | Wait until a fixed one-way countdown reaches zero.                                                            |
 |                            | [`Phaser`](https://docs.rs/asyncband/*/asyncband/phaser/struct.Phaser.html)                    | `phaser`       | Coordinate repeated phases with a dynamic participant set.                                                    |
 |                            | [`WaitGroup`](https://docs.rs/asyncband/*/asyncband/waitgroup/struct.WaitGroup.html)           | `waitgroup`    | Dynamically register participants and wait until all have completed.                                          |
+|                            | [`TaskGroup`](https://docs.rs/asyncband/*/asyncband/task_group/struct.TaskGroup.html)          | `task-group`   | Track independently spawned futures and consume their outputs in completion order.                            |
 |                            | [`Shutdown`](https://docs.rs/asyncband/*/asyncband/shutdown/struct.Shutdown.html)              | `shutdown`     | Request shutdown and wait until all completion guards are dropped.                                            |
 | Work coalescing            | [`Once`](https://docs.rs/asyncband/*/asyncband/once/struct.Once.html)                          | `once`         | Complete one asynchronous initialization; cancelled or panicked attempts may be retried.                       |
 |                            | [`OnceCell`](https://docs.rs/asyncband/*/asyncband/once/struct.OnceCell.html)                  | `once-cell`    | Store one value from an access-time initializer; failed, cancelled, or panicked attempts may be retried.       |

asyncband/Cargo.toml

@@ -65,6 +65,7 @@ rwlock = []
 semaphore = []
 shutdown = ["latch", "waitgroup"]
 singleflight = ["dep:hashbrown", "once-cell"]
+task-group = []
 waitgroup = []
 watch = []
 

asyncband/src/internal/mod.rs

@@ -90,6 +90,7 @@ pub(crate) mod value_cell;
     feature = "phaser",
     feature = "rwlock",
     feature = "semaphore",
+    feature = "task-group",
     feature = "waitgroup",
     feature = "watch",
 ))]

asyncband/src/lib.rs

@@ -65,6 +65,7 @@
 //! |                            | [`Latch`](latch::Latch)                       | `latch`        | Wait until a fixed one-way countdown reaches zero.                                                            |
 //! |                            | [`Phaser`](phaser::Phaser)                    | `phaser`       | Coordinate repeated phases with a dynamic participant set.                                                    |
 //! |                            | [`WaitGroup`](waitgroup::WaitGroup)           | `waitgroup`    | Dynamically register participants and wait until all have completed.                                          |
+//! |                            | [`TaskGroup`](task_group::TaskGroup)          | `task-group`   | Track independently spawned futures and consume their outputs in completion order.                            |
 //! |                            | [`Shutdown`](shutdown::Shutdown)              | `shutdown`     | Request shutdown and wait until all completion guards are dropped.                                            |
 //! | Work coalescing            | [`Once`](once::Once)                          | `once`         | Complete one asynchronous initialization; cancelled or panicked attempts may be retried.                       |
 //! |                            | [`OnceCell`](once::OnceCell)                  | `once-cell`    | Store one value from an access-time initializer; failed, cancelled, or panicked attempts may be retried.       |
@@ -161,13 +162,20 @@ pub mod semaphore;
 pub mod shutdown;
 #[cfg(feature = "singleflight")]
 pub mod singleflight;
+#[cfg(feature = "task-group")]
+pub mod task_group;
 #[cfg(feature = "waitgroup")]
 pub mod waitgroup;
 #[cfg(feature = "watch")]
 pub mod watch;
 
 #[cfg(all(
     test,
-    any(feature = "once-map", feature = "phaser", feature = "singleflight")
+    any(
+        feature = "once-map",
+        feature = "phaser",
+        feature = "singleflight",
+        feature = "task-group"
+    )
 ))]
 mod test_support;