Call func for each session managed by this.
The result value of func determines what happens to the session. func will be called with
this locked so no further actions on this can be performed from
func.
If func returns REMOVE, the session will be removed
from this.
If func returns KEEP, the session will remain in
this.
If func returns REF, the session will remain in
this but will also be added with an additional ref to the result List of this
function..
When func is null, REF
will be assumed for each session.
| this |
a Client |
| func |
a callback |
| user_data |
user data passed to |
|
a List with all sessions for which |