Thanks Julien, I forgot about this part, will create a new PR.
I thought referencing the abstract of the algorithm + a link to the IETF RFC:
Happy Eyeballs: Success with Dual-Stack Hosts
When a server's IPv4 path and protocol are working, but the server's
IPv6 path and protocol are not working, a dual-stack client
application experiences significant connection delay compared to an
IPv4-only client. This is undesirable because it causes the dual-
stack client to have a worse user experience. This document
specifies requirements for algorithms that reduce this user-visible
delay and provides an algorithm.
https://tools.ietf.org/html/rfc6555