The “Share Internet Connection” built into High Sierra enables your Lightning-to-USB devices running iOS 10.3 or later to share the Internet Connection of the Mac. In my tests I’ve been able to match my desktop download/upload speeds ~ in my case this is a 70mb download and 5mb upload speed (maximum of my ISP plan). 
The feature previously baked into Mac OS Server, is now a native part of OS with High Sierra. It works with any iOS device on 10.3 or later.
Here’s what you need:
- Mac Connected to Internet via Ethernet
- iOS Device connected to Mac via Lightning-to-USB Cable
- Internet Sharing Enabled (System Preferences–>Sharing–>Content Caching
And that’s it. In my tests I got the full download/upload speed capacity of my home network over the connection:
Secret internet level unlocked. pic.twitter.com/QFiM2CkP1F
— Aud-iOS (@Aud_iOS) August 11, 2017
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One note, if you use IDAM (Inter Device Audio & MIDI Mode) it disables the shared connection.
Here’s the full August 21, 2017 article by Apple on Content Caching Services
Categories: AOIP - Networked Audio, Audio Optimization Resources, iOS, iOS 11, iOS Music Production, macOS High Sierra, Music Production, USB Audio & MIDI