--- /dev/null
+var call = require('../internals/function-call');
+var AsyncFromSyncIterator = require('../internals/async-from-sync-iterator');
+var anObject = require('../internals/an-object');
+var getIterator = require('../internals/get-iterator');
+var getMethod = require('../internals/get-method');
+var wellKnownSymbol = require('../internals/well-known-symbol');
+
+var ASYNC_ITERATOR = wellKnownSymbol('asyncIterator');
+
+module.exports = function (it, usingIterator) {
+ var method = arguments.length < 2 ? getMethod(it, ASYNC_ITERATOR) : usingIterator;
+ return method ? anObject(call(method, it)) : new AsyncFromSyncIterator(getIterator(it));
+};