Is it really 100% Go? It does not seem that the UI bits are written in Go -- they likely just pull in the Ivy bits via JNI (e.g., via [1]) and implement the rest of the application in Java. The language on the page also seems to indicate this[2]. I'm much more interested to see Go/Android interop include support for interacting with the native UI within an entirely Go application without having to jump through the JNI hoops myself (though the benefits to this are admittedly tenuous at best).
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[1] https://godoc.org/golang.org/x/mobile/app
[2] "A more complete description of the underlying engine is available at http://godoc.org/robpike.io/ivy."