public function __construct(callable $emitter)
{
$result = $emitter($this->callableFromInstanceMethod("emit"));
if (!$result instanceof \Generator) {
throw new \Error("The callable did not return a Generator");
}
Loop::defer(function () use($result) {
$coroutine = new Coroutine($result);
$coroutine->when(function ($exception, $value) {
if ($this->resolved) {
return;
}
if ($exception) {
$this->fail($exception);
return;
}
$this->resolve($value);
});
});
}