Updates a set of agent settings.

If the argument "key" has the value "policy": updates the global agent settings.

• See for agent setting names and values.
• Zero or more of such settings can be specified.
  • If a setting isn't specified, its previous value is deleted. The corresponding default
    value will take the place of the previous value on the next call to
    .
• See for restrictions on the values of the
  settings.
  • If at least one value is invalid, the entire set of settings is discarded.