One of several symbols used to identify a hook, as listed below.
The arguments of the function that is to run when the event occurs.
This function runs a hook that was previously set up with add_hook. The currently available hooks are:
| taskstarted_hook |
| taskdied_hook |
| exception_hook |
| echo_hook |
| gc_hook |
| trace_symbol_hook |
| trace_entry_hook |
| trace_exit_hook |
| breakpoint_hook |