 LDAP server
(<em>request control</em>) or a control returned by an LDAP server
(<em>response control</em>).  Unlike extended requests and responses,
there is not necessarily any pairing between request controls and
response controls.  You can send request controls and expect no
response controls back, or receive response controls without sending
any request controls.
<p>
An application typically does not deal directly with this interface.
Instead, it deals with classes that <em>implement</em> this interfac