Course of Raku / Functional, concurrent, reactive, and web programming / Reactive programming / react and whenever / whenever

Quiz — whenever

What does the following program print?

my @out;

react {
    whenever Supply.from-list(1, 2, 3) {
        @out.push($_ * 2);
    }
}

say @out;
0[1 2 3]
1[2 4 6]
0[6]
012

The whenever body runs for each value, pushing twice its value. The supply emits 1, 2, 3, so @out collects 2, 4, 6.

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