I'm using Go 1.6 and want to make a HTTP2-only request over http://.
Attempting to do this currently results in:
Head http://localhost:2076/completed/764c1b6bc55548707507a2dd25570483a7216bf4: http2: unsupported scheme
To force http2, I believe I need http.Client.Transport.TLSConfig.NextProtos set to []string{"h2"}.
What else is required?
You need to use https, not http. The http2 transport doesn't recognize the http scheme.
The HTTP/2.0 by default works on highly secured connections. It uses high quality ciphers. So it can only run on HTTPS connections. Moreover, to make HTTPS connections, you also need to have your SSL enabled and have the required certificates installed.