pkg net, method (*OpError) Unwrap() error
pkg net, type DNSError struct, IsNotFound bool
pkg net, type ListenConfig struct, KeepAlive time.Duration
pkg net/url, method (*Error) Unwrap() error
pkg os/exec, method (*Cmd) String() string
pkg os/exec, method (*Error) Unwrap() error
pkg os, func UserConfigDir() (string, error)
pkg os, method (*LinkError) Unwrap() error
pkg os, method (*PathError) Unwrap() error

type myString string
myString('\u65e5')   // "\u65e5" == "日" == "\xe6\x97\xa5"
</pre>

Note: This form of conversion may eventually be removed from the language.
The <a href="/pkg/cmd/vet"><code>go vet</code></a> tool flags certain
integer-to-string conversions as potential errors.
Library functions such as
<a href="/pkg/unicode/utf8#AppendRune"><code>utf8.AppendRune</code></a> or