An interesting go-ish thing to do regarding: """Now, DownloadAndVerifyThing is shorter, contains less state, and is more obviously a composition of several tasks."""
...I've experimented with "convert a long sequential, independent function into several internal anonymous functions" (ie: similar to IIFE in javascript).
This generally prevents (or contains) variable leakage and prevents (or contains) "complexity leakage".
In their example: `DownloadAndVerifyThing(...) { ... }`, those functions could be defined internal to the `DownloadAndVerifyThing` function, which is kindof a further form of comment: "thou shalt not be using these weird functions outside of this particular function which does the downloading and verifying..."
Even if it's done not in a function but in an anonymous block, "trapping" any state leakage or side-effects is nice for complexity reduction.
Example:
func Foo() bar {
{
x := 1
y := 2
...lots of math, etc...
}
abc := 123
}