call site.
</p>

<p>
Given the function and calls
</p>
<pre>
func Greeting(prefix string, who ...string)
Greeting("nobody")
Greeting("hello:", "Joe", "Anna", "Eileen")
</pre>

<p>
within <code>Greeting</code>, <code>who</code> will have the value
<code>nil</code> in the first call, and
<code>[]string{"Joe", "Anna", "Eileen"}</code> in the second.

	case <-sc.doneServing:
	}
}

var http2errPrefaceTimeout = errors.New("timeout waiting for client preface")

// readPreface reads the ClientPreface greeting from the peer or
// returns errPrefaceTimeout on timeout, or an error if the greeting
// is invalid.
func (sc *http2serverConn) readPreface() error {
	if sc.sawClientPreface {
		return nil
	}
	errc := make(chan error, 1)
	go func() {