@basic-streams/map3

``typescript
map3(
fn: (a: A, b: B, c: C) => D,
streamA: Stream,
streamB: Stream,
streamC: Stream,
): Stream
`

Creates a stream containing fn(a, b, c) where a, b and c are the latest
values from streamA, streamB and streamC. The resulting stream updates
when any of source stream update.

`js
import ofMany from "@basic-streams/of-many"
import map3 from "@basic-streams/map3"

const streamA = ofMany([2, 4], 10000)
const streamB = ofMany([1, 3], 8000)
const streamC = ofMany([0], 3000)
const result = map3((a, b, c) => a + b + c, streamA, streamB, streamC)

result(x => {
console.log(x)
})

// > 3
// > 5
// > 7

// streamA: _________2_________4
// streamB: _______1_______3
// streamC: __0
// result: _________3_____5___7
``