<apply-trap> class implements traps that are triggered upon
any procedure application. No further parameters are needed to
specify an instance of this class, so there are no class-specific trap
options. Note that it remains possible to use the common trap options
(see Common Trap Options), for example to set a trap for the next
application where some condition is true.
(install-trap (make <apply-trap> #:condition my-condition #:behaviour gds-debug-trap))