reduce.concurrent

```coffeescript
Reducer = (any, T)=>Promise|any
Foldable = Iterable|AsyncIterable|{ reduce: Reducer=>any }|Object

reduce.concurrent(
data Foldable,
reducer (any, any)=>Promise|any,
result any,
) -> Promise|any

reduce.concurrent(
reducer (any, any)=>Promise|any,
result any,
)(data Foldable) -> Promise|any
```

Concurrent `reduce`. Reduce operation happens by order of asynchronous resolution and then the order of data argument.

```javascript
reduce.concurrent(
[1, 2, 3],
async (total, number) => {
await Promise(resolve => setTimeout(resolve, number))
return total + number
},
0,
).then(console.log) // 6
```