Function queue

queue(
    concurrency?: number,
): {
    add: <T>(task: () => Promise<T>) => Promise<T>;
    running: () => number;
    size: () => number;
}
Creates an async task queue with controlled concurrency.

Tasks are executed in FIFO order, respecting the concurrency limit. Each add call returns a promise that resolves/rejects with the task result.
Parameters
- concurrency: number = 1
  Maximum number of tasks running at once (default: 1).
Returns {
    add: <T>(task: () => Promise<T>) => Promise<T>;
    running: () => number;
    size: () => number;
}
An object with methods to add tasks and inspect queue state.
- add: <T>(task: () => Promise<T>) => Promise<T>
  Add a new async task to the queue.
- running: () => number
  Returns the number of currently active/running tasks.
- size: () => number
  Returns the number of pending tasks in the queue.
Example
```
const q = queue(2);

for (let i = 0; i < 5; i++) {
  q.add(async () => {
    console.log("Task", i, "started");
    await new Promise(r => setTimeout(r, 100));
    console.log("Task", i, "done");
    return i * 2;
  }).then(result => console.log("Result:", result));
}
```
Since
1.2.0
- Defined in async/queue.ts:27