new CommonIterator(handler, channel_id, txID, response)
close the iterator.
Returns:A promise that is resolved with the close payload or rejected if there is a problem
Get the next value and return it through a promise and also emit it if event listeners have been registered.
Returns:a promise that is fulfilled with the next value. If there is no more next value, "done" key of the object is true. It is rejected if any error occurs.