> No Optional Arguments: Go only has variadic functions which are similar to Python’s keyword arguments, but less useful, since the arguments need to be of the same type.

What I like to do is to make the last arg take a struct such that you indirectly have named (and optional) arguments:

  type DownloadOpts struct {
    UserAgent string
    TimeoutSeconds int
    //...
  }

  func Download(url string, opts DownloadOpts) (io.Reader, error) {
    ...
  }

  //use like:
  contents, err := Download("https://news.ycombinator.com", DownloadOpts {
    UserAgent: "example-snippet/1.0",
  })

> Never needing to pause for garbage collection could also be a factor [in Rust's greater speed compared to Go].

Would be nice if the author had checked

  var ms runtime.MemStats
  runtime.ReadMemStats(&ms)
  print(ms.NumGC)

to see if there was actually any garbage collection performed.