Function map

map<V, R>(mapper: (item: NoInfer<V>) => Awaitable<R>): Task<V, R>
Creates a task converting each item into a new value.

Items are emitted in source order.
Note
- Incremental: items are emitted as they are drawn, so the reported feed runs dry as the feed drawn from does.
- Streaming: items are converted one at a time, none retained.
- Stateless: every item is converted on its own, so the outcome is unaffected by how the feed is split across nested feeds or runs.
Type Parameters
- V
  The type of input items
- R
  The type of output items
Parameters
- mapper: (item: NoInfer<V>) => Awaitable<R>
  The function converting each item
Returns Task<V, R>
A task yielding the values mapper converts the items into
Example
```
await pipe(
  (items([1, 2, 3]))
  (map(n => n*2))
  (toArray())
);  // [2, 4, 6]
```
- Defined in tasks/map.ts:52