Why v2rayN switch Tun backend to sing box?

[hugo-sama]

As these issues occurred, it looks like not been tested before it release.
So that makes me wonder why this project changed this? Pretty radical IMHO.

#4539
#4539 (comment)

Why do you even need to use Sing-Box completely instead of combining them both like NekoRay? Sing-Box does not support mux.cool/fragment/xray's quic and mkcp and more, you can't convert xray's conf to sing-box and Xray-core does not support sing-box's mux (connection will fail) This was a bad idea to convert xray/v2ray configs to sing-box for Tun!