class select_based_event_system :This the oldunit ->sb_event_system
Unix.select-based imeplementation of event systems
which was the default one until Ocamlnet-2.2.
Please avoid in new code. This module merely exists to allow comparisons between the old implementation and the new one.
Note that this class definition also includes some private
methods. These are required in some other Unixqueue implementations
inheriting from this class.
