asObservable

import std.range : iota;

auto obs = from(iota(10));
auto res = new int[10];
auto d = obs.subscribe(res[]);
scope (exit)
    d.dispose();

assert(res.length == 10);
assert(res[0] == 0);
assert(res[9] == 9);

import std.range : iota;

auto obs = iota(10).asObservable();
auto res = new int[10];
auto d = obs.subscribe(res[]);
scope (exit)
    d.dispose();

assert(res.length == 10);
assert(res[0] == 0);
assert(res[9] == 9);