bifystatechangeI
I couldn't find any information on "bifystatechangeI". However, I think you may be referring to "Bisync" or "Batch Intermediate Synchronization" may not directly relate, but "bifromsynchronous to asynchronous" or a prefix "bi" as a short form and "ynchronous" a word indicating a real time process I did find the term "bisynchronous" which is even more related.
Bisynchronous communication involves the exchange of data between two devices, with each device generating and receiving
A primer on Bisync might indicate: The Bisync protocol is a standards-based data communications protocol developed
Bisync is widely used in industrial automation and other high-speed serial data transfer applications.