/// @ref LibraryHandle::registerCommandHandler can install callouts on this
/// hook point.
///
-/// The @ref CalloutManager::registerCommandHandler is called from the
-/// @ref LibraryHandle object when the hook library installs control command
-/// handlers in its @c load() function.
-///
/// Note that the callout functions do not access the CalloutManager: instead,
/// they use a LibraryHandle object. This contains an internal pointer to
/// the CalloutManager, but provides a restricted interface. In that way,