While it is acceptable syntax, it is unnecessary and not recommended by
the PHP documentation:
https://secure.php.net/manual/en/language.namespaces.importing.php#language.namespaces.importing
> Note that for namespaced names (fully qualified namespace names
> containing namespace separator, such as Foo\Bar as opposed to global
> names that do not, such as FooBar), the leading backslash is
> unnecessary and not recommended, as import names must be fully
> qualified, and are not processed relative to the current namespace.
