Should use native Promise when possible

[dzag]

Fix #139

[marinaserranomontes]

Thanks for the contribution @dzag! I think Native Promises is a good approach and even the old fallback logic is no longer needed.
Since this PR has been inactive for a few years and the codebase has changed, we’re closing it to keep things tidy. If you’d like to revisit the idea, feel free to open a new PR. Thanks again!