Otherwise, <code>append</code> re-uses the underlying array.
</p>

<pre>
s0 := []int{0, 0}
s1 := append(s0, 2)                // append a single element     s1 == []int{0, 0, 2}
s2 := append(s1, 3, 5, 7)          // append multiple elements    s2 == []int{0, 0, 2, 3, 5, 7}
s3 := append(s2, s0...)            // append a slice              s3 == []int{0, 0, 2, 3, 5, 7, 0, 0}