Observable::of(Observable::fromArray([1, 2, 3, 4, 5]))
->filter(\Rx\is(Observable::class))
->mergeAll()
->filter(\Rx\notEqualTo(2))
->filter('rx\even')
->reduce('rx\add')
->map(\Rx\p('rx\mult', 3))
->map(\Rx\p('rx\sub', 2))
->map(\Rx\p('rx\concatLeft', 'total: '))
->compose(\Rx\echoFinally('Test '))
->subscribe(\Rx\echoObserver('Test '));
//Test Next value: total: 10
//Test Complete!
//Test Finally!