/REQUEST_INPUT="hot-key-defintion"

   Hot-key used to gain temporary ability to control the keyboard of
   the user being watched when the watcher wouldn't normally be able to
   gain keyboard control due to licensing or ALLOW-command restrictions.

   Use of the REQUEST_INPUT hot-key by a watcher only succeeds if the user
   being watched (or primary watcher) has first successfully issued a
   PERMIT_INPUT by using his PERMIT_INPUT hot-key.

   A second REQUEST_INPUT issued by the watcher after his REQUEST_INPUT
   has been granted, toggles his REQUEST_INPUT back off again.

   A REQUEST_INPUT request will fail if another watcher has already
   accepted the PERMIT_INPUT, or if REQUEST_INPUT hasn't first been
   permitted by a successful PERMIT_INPUT issued by the user being
   watched or primary watcher.

   If a REQUEST_INPUT is unsuccessful, the terminal will just beep.

   When a REQUEST_INPUT is successful, the watcher who did the successful
   REQUEST_INPUT may temporarily provide input. The TOGGLE_INPUT key may
   need to be used, unless the PSIMUL qualifier (or default) is in effect.

   The user (or primary watcher) who issued the PERMIT_INPUT may revoke it
   again at any time by again typing his PERMIT_INPUT hot-key sequence.

   A PERMIT_INPUT by the user being watched is also revoked if a primary
   watcher does a TOGGLE_INPUT to take keyboard control from the user.

   Likewise, a PERMIT_INPUT by the primary watcher is revoked if the user
   being watched does a TOGGLE_INPUT to take keyboard control back from
   the primary watcher.

   Thus input-ability gain through REQUEST_INPUT is very temporary.

   Note that PERMIT_INPUT and REQUEST_INPUT may be used to temporarily
   grant input-ability to a watcher who otherwise would not be able to
   gain keyboard control due to licensing option or ALLOW-command
   restrictions.

   The logical WATCHER$REQUEST_INPUT specifies the default hot-key value.