Illegal rune litteral in Go example

[zeidlitz]

in golang-calls.go on line 17 the error "Illegal rune literal" occurs because in Go, single quotes are used for character (rune) literals, not for strings. However, in your code, you are trying to define a JSON string within single quotes, which Go interprets as a rune literal.

This can easily be adjusted with a set of backticks or double quotes for string literals like so:

data := url.Values{
    "from":        {"+46709751949"},
    "to":          {"+46700000000"},
    "voice_start": {`{"connect":"+461890510"}`},
}

Might be very nitpick but this will make so the code example can compile out of the box ✌