Sometime it is convenient to get recursive directory listing as array of items
directory => (file array)
Such as:

Array
(
[./a2temple] => Array
(
[0] => example13.zip
)

[./rand] => Array
(
[0] => rand.zip
)

[./pstudio] => Array
(
[0] => pstudio.zip
)

[./myview/private] => Array
(
[0] => logs.zip
)

[./myview] => Array
(
[0] => myview-2.zip
)

[.] => Array
(
[0] => testutf.zip
[1] => RBAC.ZIP
)

)

My function can get optional extension filter and returns count of files found.